Effects of a 6-week hypocaloric diet on changes in body composition, hunger, and subsequent weight regain in healthy young and older adults

Is dieting a risk for higher weight gain in normal-weight individual? A systematic review and meta-analysis

While there is an increasing prevalence of dieting in the overall population, weight loss (WL) practices could be a risk factor for weight gain (WG) in normal-weight (NW) individuals. The aim of the present work was to systematically review all the studies implicating diet restriction and body weight (BW) evolution in NW people. The literature search was registered in PROSPERO (CRD42021281442) and was performed in three databases from April 2021 to June 2022 for articles involving healthy NW adults. From a total of 1487 records initially identified, eighteen were selected in the systematic review. Of the eight dieting interventional studies, only one found a higher BW after weight recovery, but 75 % of them highlighted metabolic adaptations in response to WL favouring weight regain and persisting during/after BW recovery. Eight of the ten observational studies showed a relationship between dieting and major later WG, while the meta-analysis of observational studies results indicated that 'dieters' have a higher BW than 'non-dieters'. However, considering the high methodological heterogeneity and the publication bias of the studies, this result should be taken with caution. Moreover, the term 'diet' was poorly described, and we observed a large heterogeneity of the methods used to assess dieting status. Present results suggest that dieting could be a major risk factor for WG in the long term in NW individuals. There is, however, a real need for prospective randomised controlled studies, specifically assessing the relationship between WL induced by diet and subsequent weight in this population.

Malnutrition is associated with six-month mortality in older patients admitted to the emergency department with hip fracture

Background

Hip fractures in older people are a common health problem often associated with malnutrition that might affect outcomes. Screening for malnutrition is not a routine examination in emergency departments (ED). This analysis of the EMAAge study, a prospective, multicenter cohort study, aimed to evaluate the nutritional status of older patients (≥ 50 years) with hip fracture, factors associated with malnutrition risk, and the association between malnutrition and the six-months mortality.

Methods

Risk of malnutrition was evaluated using the Short Nutritional Assessment Questionnaire. Clinical data as well as data on depression and physical activity were determined. Mortality was captured for the first six months after the event. To assess factors associated with malnutrition risk we used a binary logistic regression. A Cox proportional hazards model was used to assess the association of malnutrition risk with six-month survival adjusted for other relevant risk factors.

Results

The sample consisted of N = 318 hip fracture patients aged 50 to 98 (68% women). The prevalence of malnutrition risk was 25.3% (n = 76) at the time of injury. There were no differences in triage categories or routine parameters measured in the ED that could point to malnutrition. 89% of the patients (n = 267) survived for six months. The mean survival time was longer in those without malnutrition risk (171.9 (167.1-176.9) days vs. 153.1 (140.0-166.2) days). The Kaplan Meier curves and the unadjusted Cox regression (Hazard Ratio (HR) 3.08 (1.61-5.91)) showed differences between patients with and patients without malnutrition risk. In the adjusted Cox regression model, risk of death was associated with malnutrition risk (HR 2.61, 1.34-5.06), older age (70-76 years: HR 2.5 (0.52-11.99); 77-82 years: HR 4.25 (1.15-15.62); 83-99 years: HR 3.82 (1.05-13.88)) and a high burden of comorbidities (Charlson Comorbidity Index ≥3: HR 5.4 (1.53-19.12)).

Conclusion

Risk of malnutrition was associated with higher mortality after hip fracture. ED parameters did not differentiate between patients with nutritional deficiencies and those without. Therefore, it is particularly important to pay attention to malnutrition in EDs to detect patients at risk of adverse outcomes and to initiate early interventions.

Implicit satiety goals and food-related expectations predict portion size in older adults: Findings from the BAMMBE cohort

Portion size selection is an indicator of appetite and within younger adults, is predicted by factors such as expected satiety, liking and motivations to achieve an ideal sensation of fullness (i.e., implicit satiety goals). Currently, there is limited research available on the determinants of portion size selection within older adults. Therefore, the current study aimed to examine the relationship between individual differences in implicit satiety goals, food-related expectations, and portion size selection in older adults. Free-living older adult Singaporeans (N = 115; Nmales = 62; age: M = 66.21 years, SD = 4.78, range = 60-83 years) participated as part of the Brain, Ageing, Microbiome, Muscle, Bone, and Exercise Study (BAMMBE). Participants completed questionnaires on their subjective requirements for experiencing different states of satiety and food-related expectations (i.e., liking, how filling) as well as a computerised portion size selection task. Using a multiple regression, we found that goals to feel comfortably full (B = 3.08, SE = 1.04, t = 2.96, p = .004) and to stop hunger (B = -2.25, SE = 0.82, t = -2.75, p = .007) significantly predicted larger portion size selection (R2 = 0.24, F(4,87) = 6.74, p < .001). Larger portion sizes (R2 = 0.53, F(5,90) = 20.58, p < .001) were also predicted by greater expected satiety (B = 0.47, SE = 0.09, t = 5.15, p < .001) and lower perceptions of how filling foods are (B = -2.92, SE = 0.77, t = -3.79, p < .001) but not liking (B = -0.09, SE = 0.91, t = -0.10, p = .925) or frequency (B = -18.42, SE = 16.91, t = -1.09, p = .279) of consumption of target foods. Comparing our findings to results of studies conducted with younger adults suggests the influence of factors such as satiety related goals on portion size selection may change with ageing while the influence of other factors (e.g., expected satiety/fullness delivered by foods) may remain consistent. These findings may inform future strategies to increase/decrease portion size accordingly to ensure older adults maintain an appropriate healthy weight.

Augenmerk auf die Ernährung im Alter

Jenseits des 70. Lebensjahrs ist bei älteren Menschen regelhaft eine Abnahme der Muskelmasse sowie eine Zunahme der Fettmasse zu beobachten. Diese Veränderungen der Körperzusammensetzung stellen eine wesentliche Prädisposition für den im Alter drohenden Verlust an Funktionalität und Selbstständigkeit dar. In diesem Kontext kommt der richtigen Ernährung sowie insbesondere dem Vermeiden einer Mangelernährung große Relevanz zu. Da die ältere Bevölkerung hinsichtlich der Geschwindigkeit und Ausprägung der Alterungsvorgänge sowie ihrer Komorbiditäten als äußerst heterogen zu betrachten ist, müssen Ernährungsempfehlungen individualisiert erfolgen. In Hinblick auf eine potenzielle Gefährdung durch eine Sarkopenie ist selbst eine beabsichtigte Gewichtsabnahme im Alter kritisch zu sehen. Fastenepisoden sollten generell vermieden werden. Dies betrifft insbesondere eine unzureichende Kalorienzufuhr im Kontext von akuten oder chronischen Erkrankungen. Im höheren Lebensalter sollten daher regelmäßige Gewichtskontrollen erfolgen, um das Auftreten einer Mangelernährung frühzeitig zu erkennen und entsprechende Maßnahmen einleiten zu können. Zum Erhalt der Muskelmasse und -funktion sollte eine gegenüber jüngeren Menschen erhöhte Eiweißzufuhr von 1,0 g/kgKG angestrebt werden. Bei älteren Menschen mit Sarkopenie wird dieses Ziel auf 1,2 g/kg KG angehoben. Während sich im Alter restriktive Diäten als nachteilig erweisen können, scheinen gesunde Ernährungsformen wie z. B. die mediterrane Ernährung den Erhalt der muskulären und kognitiven Funktion zu fördern.

Ernährung im Alter – ein wesentlicher Schlüssel zum Erhalt der Funktionalität und Lebensqualität

Jenseits des 70. Lebensjahrs ist bei älteren Menschen regelhaft eine Abnahme der Muskelmasse sowie eine Zunahme der Fettmasse zu beobachten. Diese Veränderungen der Körperzusammensetzung stellen eine wesentliche Prädisposition für den im Alter drohenden Verlust an Funktionalität und Selbständigkeit dar. In diesem Kontext kommt der richtigen Ernährung sowie insbesondere dem Vermeiden einer Mangelernährung große Relevanz zu. Da die ältere Bevölkerung hinsichtlich der Geschwindigkeit und Ausprägung der Alterungsvorgänge sowie ihrer Komorbiditäten als äußerst heterogen zu betrachten ist, müssen Ernährungsempfehlungen individualisiert erfolgen. Mit Hinblick auf eine potenzielle Gefährdung durch eine Sarkopenie ist selbst eine beabsichtigte Gewichtsabnahme im Alter kritisch zu sehen. Fastenepisoden sollten generell vermieden werden. Dies betrifft insbesondere eine unzureichende Kalorienzufuhr im Kontext von akuten oder chronischen Erkrankungen. Im höheren Lebensalter sollten daher regelmäßige Gewichtskontrollen erfolgen, um das Auftreten einer Mangelernährung frühzeitig zu erkennen und entsprechende Maßnahmen einleiten zu können. Zum Erhalt der Muskelmasse und -funktion sollte eine gegenüber jüngeren Menschen erhöhte Eiweißzufuhr von 1,0 g/kgKG angestrebt werden. Bei älteren Menschen mit Sarkopenie wird dieses Ziel auf 1,2 g/kgKG angehoben. Während sich im Alter restriktive Diäten als nachteilig erweisen können, scheinen gesunde Ernährungsformen wie z. B. die mediterrane Ernährung den Erhalt der muskulären und kognitiven Funktion zu fördern.

Ernährung im Alter – ein wesentlicher Schlüssel zum Erhalt der Funktionalität und Lebensqualität

Jenseits des 70. Lebensjahrs ist bei älteren Menschen regelhaft eine Abnahme der Muskelmasse sowie eine Zunahme der Fettmasse zu beobachten. Diese Veränderungen der Körperzusammensetzung stellen eine wesentliche Prädisposition für den im Alter drohenden Verlust an Funktionalität und Selbständigkeit dar. In diesem Kontext kommt der richtigen Ernährung sowie insbesondere dem Vermeiden einer Mangelernährung große Relevanz zu. Da die ältere Bevölkerung hinsichtlich der Geschwindigkeit und Ausprägung der Alterungsvorgänge sowie ihrer Komorbiditäten als äußerst heterogen zu betrachten ist, müssen Ernährungsempfehlungen individualisiert erfolgen. Mit Hinblick auf eine potenzielle Gefährdung durch eine Sarkopenie ist selbst eine beabsichtigte Gewichtsabnahme im Alter kritisch zu sehen. Fastenepisoden sollten generell vermieden werden. Dies betrifft insbesondere eine unzureichende Kalorienzufuhr im Kontext von akuten oder chronischen Erkrankungen. Im höheren Lebensalter sollten daher regelmäßige Gewichtskontrollen erfolgen, um das Auftreten einer Mangelernährung frühzeitig zu erkennen und entsprechende Maßnahmen einleiten zu können. Zum Erhalt der Muskelmasse und -funktion sollte eine gegenüber jüngeren Menschen erhöhte Eiweißzufuhr von 1,0 g/kgKG angestrebt werden. Bei älteren Menschen mit Sarkopenie wird dieses Ziel auf 1,2 g/kgKG angehoben. Während sich im Alter restriktive Diäten als nachteilig erweisen können, scheinen gesunde Ernährungsformen wie z. B. die mediterrane Ernährung den Erhalt der muskulären und kognitiven Funktion zu fördern.

POSSIBLE ROLE OF NUTRITION IN PREVENTION OF SARCOPENIA AND FALLS

Objective: In this review, we analyze the foundation of sarcopenia as a potentially modifiable risk factor for falls, and we try to formulate practical strategies for nutritional interventions aimed at reducing the risk for sarcopenia and falls in our elderly patients. Methods: An extensive literature search was performed using the PubMed and the Google Scholar databases. Results: Falls are a common and costly source of injury and death in elderly adults. A large proportion of injurious falls are due to a trip or slip, suggesting that muscular factors are major determinants of both fall risk and the risk for fall-related injury. Conclusion: An increasing body of evidence links sarcopenia, the loss of muscle strength and mass that occurs with advancing age, with an increased risk for falls. Nutritional factors, as well as exercise, can help with both prevention and treatment of sarcopenia and may reduce the risk of falls in the elderly. Abbreviations: 25-OHD = 25-hydroxyvitamin D; EAA = essential amino acid; IGF-1 = insulin-like growth factor 1; IU = international units; MPS = muscle protein synthesis; PUFA = polyunsaturated fatty acid.

Long-Term Weight Loss With Metformin or Lifestyle Intervention in the Diabetes Prevention Program Outcomes Study

BACKGROUND

Identifying reliable predictors of long-term weight loss (LTWL) could lead to improved weight management.

OBJECTIVE

To identify some predictors of LTWL.

DESIGN

The DPP (Diabetes Prevention Program) was a randomized controlled trial that compared weight loss with metformin, intensive lifestyle intervention (ILS), or placebo. Its Outcomes Study (DPPOS) observed patients after the masked treatment phase ended. (ClinicalTrials.gov: NCT00004992 and NCT00038727).

SETTING

27 DPP and DPPOS clinics.

PARTICIPANTS

Of the 3234 randomly assigned participants, 1066 lost at least 5% of baseline weight in the first year and were followed for 15 years.

MEASUREMENTS

Treatment assignment, personal characteristics, and weight.

RESULTS

After 1 year, 289 (28.5%) participants in the metformin group, 640 (62.6%) in the ILS group, and 137 (13.4%) in the placebo group had lost at least 5% of their weight. After the masked treatment phase ended, the mean weight loss relative to baseline that was maintained between years 6 and 15 was 6.2% (95% CI, 5.2% to 7.2%) in the metformin group, 3.7% (CI, 3.1% to 4.4%) in the ILS group, and 2.8% (CI, 1.3% to 4.4%) in the placebo group. Independent predictors of LTWL included greater weight loss in the first year in all groups, older age and continued metformin use in the metformin group, older age and absence of either diabetes or a family history of diabetes in the ILS group, and higher fasting plasma glucose levels at baseline in the placebo group.

LIMITATION

Post hoc analysis; examination of nonrandomized subsets of randomized groups after year 1.

CONCLUSION

Among persons with weight loss of at least 5% after 1 year, those originally randomly assigned to metformin had the greatest loss during years 6 to 15. Older age and the amount of weight initially lost were the most consistent predictors of LTWL maintenance.

PRIMARY FUNDING SOURCE

National Institutes of Health.

Need for Weight Management among Postmenopausal Early Breast Cancer Patients Receiving Adjuvant Endocrine Therapy

Increasingly effective adjuvant therapies mean that the prognosis for postmenopausal women with breast cancer has never been better. Weight problems are common among breast cancer patients and worsen due to the impact of diagnosis and treatment. Recent studies have linked excess weight with the risk of recurrence of breast cancer among premenopausal women. While general obesity (body mass index) does not appear to influence the already much improved prognosis for postmenopausal women, there is some evidence that limiting central obesity and improving insulin resistance may improve survival. The focus of attention for postmenopausal breast cancer survivors is also shifting to consider the mortality and morbidity from other weight-related cancers and noncancer causes, such as cardiovascular disease, making weight control a potentially important adjunct to endocrine therapy. This paper outlines the rationale and optimal design for effective weight management strategies among postmenopausal breast cancer patients receiving endocrine therapy.

Ageing Is Associated with Decreases in Appetite and Energy Intake--A Meta-Analysis in Healthy Adults

It is not well recognized that in the elderly weight loss is more common than weight gain. The aim of this analysis was to determine the effect of ageing on appetite (hunger/fullness) and energy intake, after overnight fasting and in a postprandial state, by meta-analyses of trials that included at least two age groups (>18 years). We hypothesized that appetite and energy intake would be less in healthy older compared with younger adults. Following a PubMed-database systematic search up to 30 June 2015, 59 studies were included in the random-effects-model meta-analyses. Energy intake was 16%-20% lower in older (n = 3574/~70 years/~71 kg/~25 kg/m²) than younger (n = 4111/~26 years/~69 kg/~23 kg/m²) adults (standardized mean difference: -0.77 (95% confidence interval -0.90 to -0.64)). Hunger was 25% (after overnight fasting; weighted mean difference (WMD): -17 (-22 to -13) mm) to 39% (in a postprandial state; WMD: -14 (-19 to -9) mm) lower, and fullness 37% (after overnight fasting; WMD: 6 mm (95% CI: 1 to 11 mm)) greater in older than younger adults. In conclusion, appetite and energy intake are less in healthy older than younger adults, suggesting that ageing per se affects food intake.

Fasting periods in older patients attending a South London emergency department

There is increasing recognition of the deleterious effects of poor nutrition on health care outcomes. Older patients appear particularly vulnerable to the effects of undernutrition. This includes both low intake as patients and chronic preadmission undernutrition. This study investigates nutrition during a critical intervening period when patients present to a hospital emergency department (ED) in the first half of the day. One third of observed patients sustained periadmission fasts in excess of 18 hours. This fasting period showed significant positive correlation to age (correlation coefficient = 0.34, P < 0.05). Analysis of the results by gender showed that men who were older than the average cohort age of 53.6 years fasted for a significantly longer period in the hospital than their younger counterparts (P < 0.02). This comparison did not reach significant levels for female patients (P > 0.05). This study raises the question as to whether food should be routinely provided in the ED unless there is reason to withhold it. Particular care should be taken to avoid unnecessary delays in offering food to older patients. There may also be a need to ensure that geriatric care indicators are considered individually for each gender.

Physiological and psychosocial age-related changes associated with reduced food intake in older persons

Dietary intake changes during the course of aging. Normally an increase in food intake is observed around 55 years of age, which is followed by a reduction in food intake in individuals over 65 years of age. This reduction in dietary intake results in lowered levels of body fat and body weight, a phenomenon known as anorexia of aging. Anorexia of aging has a variety of consequences, including a decline in functional status, impaired muscle function, decreased bone mass, micronutrient deficiencies, reduced cognitive functions, increased hospital admission and even premature death. Several changes during lifetime have been implicated to play a role in the reduction in food intake and the development of anorexia of aging. These changes are both physiological, involving peripheral hormones, senses and central brain regulation and non-physiological, with differences in psychological and social factors. In the present review, we will focus on age-related changes in physiological and especially non-physiological factors, that play a role in the age-related changes in food intake and in the etiology of anorexia of aging. At the end we conclude with suggestions for future nutritional research to gain greater understanding of the development of anorexia of aging which could lead to earlier detection and better prevention.

Effect of Body Composition Methodology on Heritability Estimation of Body Fatness

Heritability estimates of human body fatness vary widely and the contribution of body composition methodology to this variability is unknown. The effect of body composition methodology on estimations of genetic and environmental contributions to body fatness variation was examined in 78 adult male and female monozygotic twin pairs reared apart or together. Body composition was assessed by six methods - body mass index (BMI), dual energy x-ray absorptiometry (DXA), underwater weighing (UWW), total body water (TBW), bioelectric impedance (BIA), and skinfold thickness. Body fatness was expressed as percent body fat, fat mass, and fat mass/height2 to assess the effect of body fatness expression on heritability estimates. Model-fitting multivariate analyses were used to assess the genetic and environmental components of variance. Mean BMI was 24.5 kg/m2 (range of 17.8-43.4 kg/m2). There was a significant effect of body composition methodology (p<0.001) on heritability estimates, with UWW giving the highest estimate (69%) and BIA giving the lowest estimate (47%) for fat mass/height2. Expression of body fatness as percent body fat resulted in significantly higher heritability estimates (on average 10.3% higher) compared to expression as fat mass/height2 (p=0.015). DXA and TBW methods expressing body fatness as fat mass/height2 gave the least biased heritability assessments, based on the small contribution of specific genetic factors to their genetic variance. A model combining DXA and TBW methods resulted in a relatively low FM/ht2 heritability estimate of 60%, and significant contributions of common and unique environmental factors (22% and 18%, respectively). The body fatness heritability estimate of 60% indicates a smaller contribution of genetic variance to total variance than many previous studies using less powerful research designs have indicated. The results also highlight the importance of environmental factors and possibly genotype by environmental interactions in the etiology of weight gain and the obesity epidemic.

Circulating TNF alpha receptor levels identify older adults who fail to regain weight after acute weight loss

OBJECTIVE

Some healthy older adults have difficulty regaining weight after acute weight loss, and the reason for this failure to regain weight is unknown. The objective of this study was to determine if elevated leptin or pro-inflammatory cytokine levels are associated with failure to regain weight over two years after an acute weight loss intervention.

DESIGN

Two year prospective study after an acute weight loss intervention.

SETTING

University of Washington Medical Center from 2001-2006.

PARTICIPANTS

Nineteen older (≥ 70 years old) men and women.

MEASUREMENTS

Body weights, health status questionnaire, body composition data, serum leptin, glucose, insulin, C- reactive protein and pro-inflammatory cytokine levels were measured every six months for two years.

RESULTS

Five subjects out of 19 failed to regain weight after two years. The subjects who failed to regain weight after 2 years had higher circulating levels of tumor necrosis factor receptor particle 55 (TNFRp55) at baseline and at 6, 12, 18 and 24 months of follow up compared to subjects who regained weight after 2 years (P = 0.02 ).

CONCLUSION

Five out of 19 older subjects had difficulty regaining weight for up to 2 years following an acute weight loss intervention, and their TNFRp55 levels were persistently higher than in subjects who regained weight. Greater TNF α action, as reflected by higher circulating levels of TNFRp55, could be contributing towards inability of some older persons to regain weight after acute weight loss.

Food form and portion size affect postprandial appetite sensations and hormonal responses in healthy, nonobese, older adults

Data are limited concerning the dietary factors that influence appetite control in older adults. This study examined the effects of food form and portion size on appetite in 43 older adults (age: 72 +/- 1 years; BMI: 25.6 +/- 0.3 kg/m(2)). Subjects were assigned to groups based on portion size of the test meal (12.5% (n = 18) vs. 25% (n = 25) of estimated energy need). Subjects randomly consumed, on two separate days, the respective solid or beverage test meal. Appetite sensations and hormonal responses were measured over 4 h. Main effects of food form (P < 0.05) and/or portion size (P < 0.05) were observed for each appetite sensation. Postprandial hunger and desire to eat were greater following beverage vs. solid meal (between 12.5% vs. 25%), whereas fullness was lower after beverage vs. solid meal (P < 0.05). Main effects of food form and/or portion size were observed for glucose, insulin, and ghrelin. Postprandial glucose and insulin concentrations were lower after beverage vs. solid meal (between 12.5% vs. 25%; all comparisons, P < 0.05) whereas beverage meal led to greater 4-h ghrelin vs. solid meal (P = 0.09). No main effects were observed for glucagon-like peptide-1 (GLP-1) or cholecystokinin (CCK). When adjusting for age, food form remained significant for postprandial hunger and fullness; portion size remained significant for postprandial glucose. Greater hunger and reduced satiety with accompanying glucose, insulin, and ghrelin following the beverage vs. solid meals, and to some extent, in smaller vs. larger portions suggest that appetite control is influenced by food form and portion size in older adults. These findings may enhance the development of appropriate dietary strategies that help to regulate energy balance.

Low or moderate dietary energy restriction for long-term weight loss: what works best?

Theoretical calculations suggest that small daily reductions in energy intake can cumulatively lead to substantial weight loss, but experimental data to support these calculations are lacking. We conducted a 1-year randomized controlled pilot study of low (10%) or moderate (30%) energy restriction (ER) with diets differing in glycemic load in 38 overweight adults (mean +/- s.d., age 35 +/- 6 years; BMI 27.6 +/- 1.4 kg/m(2)). Food was provided for 6 months and self-selected for 6 additional months. Measurements included body weight, resting metabolic rate (RMR), adherence to the ER prescription assessed using (2)H(2)(18)O, satiety, and eating behavior variables. The 10%ER group consumed significantly less energy (by (2)H(2)(18)O) than prescribed over 12 months (18.1 +/- 9.8%ER, P = 0.04), while the 30%ER group consumed significantly more (23.1 +/- 8.7%ER, P < 0.001). Changes in body weight, satiety, and other variables were not significantly different between groups. However, during self-selected eating (6-12 months) variability in % weight change was significantly greater in the 10%ER group (P < 0.001) and poorer weight outcome on 10%ER was predicted by higher baseline BMI and greater disinhibition (P < 0.0001; adj R(2) = 0.71). Weight loss at 12 months was not significantly different between groups prescribed 10 or 30%ER, supporting the efficacy of low ER recommendations. However, long-term weight change was more variable on 10%ER and weight change in this group was predicted by body size and eating behavior. These preliminary results indicate beneficial effects of low-level ER for some but not all individuals in a weight control program, and suggest testable approaches for optimizing dieting success based on individualizing prescribed level of ER.

Malnutrition and depression in the institutionalised elderly

Malnutrition and depression are highly prevalent in the institutionalised elderly and can lead to unfavourable outcomes. The aim of the present study was to assess associations between nutritional status and depressive symptoms and to explore their impact on self-caring capacity and quality of life (QoL) in elderly nursing-home residents (NHR). We conducted a cross-sectional study with 114 NHR (eighty-six female) with a mean age of 84.6 (sd 9.1) years. Nutritional status was assessed with the Mini Nutritional Assessment (MNA). Depressive symptoms were rated with the Geriatric Depression Scale (GDS). Self-caring capacity was measured with the Barthel index (BI) and QoL was assessed with the short-form thirty-six-item (SF-36) questionnaire. Of the NHR, twenty-six (22.8 %) were malnourished according to the MNA and sixty-six (57.9 %) were at nutritional risk. Of the residents, seventy-five could be assessed with the GDS, whereof sixteen (21.3 %) had major and twenty-six (34.7 %) had minor depressive symptoms. GDS scores tended to be higher in patients with impaired nutritional status (5.4 (sd 3.6) in well-nourished subjects and 6.9 (sd 3.2) in residents with malnutrition or at risk of malnutrition). The MNA correlated significantly with the GDS (r - 0.313; P = 0.006) and the GDS emerged as the only independent risk factor for malnutrition in a multiple regression analysis, whereas age, sex, care level, number of prescriptions and self-caring capacity had no influence. The BI was not reduced in patients with a high GDS. QoL was affected in malnourished residents as well as in study participants with depressive symptoms. The results of the present study point towards an association between malnutrition and depressive symptoms. However, the relationship is complex and it remains unclear whether depression in NHR is the cause or consequence of impaired nutritional status. Further studies are needed to identify the direction of this relationship and to assess the effect of depression treatment on nutritional and functional status as well as on QoL.

Effect of fluid and food intake on the body composition evaluation of elderly persons

BACKGROUND

Several studies have shown that liquid and food intake interfere with the evaluation of body composition in adults. However, since there are no reports about this interference in the elderly population, the need to fast for this evaluation may be dispensable.

OBJECTIVES

The objective of the present study was to assess the influence of liquid and solid food on the measurement of body composition by bioelectrical impedance analysis (BIA) and by dual energy X-ray absorptiometry (DXA).

DESIGN

Forty-one male volunteers aged 62 to 87 years participated in the study. The subjects were submitted to evaluation of body composition by DXA and BIA under fasting conditions and 1 hour after the ingestion of breakfast (500 ml of orange juice and one 50 g bread roll with butter).

RESULTS

There was no significant difference in the variables fat-free mass (FFM) or fat mass (FM) between the fasting condition and the evaluation performed 1 hour after the meal as measured by BIA or DXA. There was also no significant difference when the same variables were compared between methods.

CONCLUSION

In the present study, the ingestion of 500 ml orange juice and of one bread roll with butter by elderly subjects did not affect the results of the parameters of body composition determined by BIA or DXA. Thus, these exams could be performed without the rigor of fasting, often poorly tolerated by the elderly.

Leptin levels recover normally in healthy older adults after acute diet-induced weight loss

OBJECTIVES

Involuntary weight loss affects 20% of community dwelling older adults. The underlying mechanism for this disorder is unknown. Objective is to determine if failure of older persons to regain weight is associated with elevated pro-inflammatory cytokine and leptin levels.

DESIGN

Prospective diet intervention study.

SETTING

University of Washington Medical Center from 2001-2005.

PARTICIPANTS

Twenty-one younger (18-35 years old) and nineteen older (>or= 70 years old) men and women.

INTERVENTION

Each subject was placed for two weeks on a weight-maintaining diet, followed in sequence by 2 weeks of 30% caloric restriction, then 4 weeks of ad libitum food intake.

MEASUREMENTS

Plasma leptin levels, fasting serum pro-inflammatory cytokine levels, and peripheral blood mononuclear cell cytokine levels were measured.

RESULTS

Leptin levels in the two cohorts decreased after caloric restriction and increased after ad-libitum food consumption resumed. Plasma TNF alpha levels were higher in older subjects compared to younger adults. However, there was no association between changes in TNF alpha levels and changes in AUC leptin.

CONCLUSION

Leptin levels in healthy older individuals responded appropriately in a compensatory manner to changes in body weight. These data do not support a cytokine dependent elevation in leptin levels as being responsible for the failure of older adults to regain weight.

Differences in eating behaviors between nonobese, weight stable young and older adults

Habitual dietary intake, dietary cognitive restraint (CR), disinhibition and hunger are eating behaviors that influence energy balance in both young and older adults. Since the prevalence of overweight and obesity in older adults is steadily rising, it is important to identify eating behavior adaptations that allow individuals to maintain a healthy body weight with advancing age. The association of age with habitual dietary intake, dietary CR, dishinhibition and hunger was examined in 30 older (60-72 years) and 30 younger (18-25 years) nonobese, weight stable, nondieting healthy adults pair-matched by age group for sex, physical activity level (active >150 min of physical activity per week, sedentary <150 min of physical activity per week) and BMI. Dietary CR was significantly greater and hunger was significantly less in older compared to young adults (both P<0.05). Disinhibition scores, habitual energy and macronutrient intake did not differ between age groups. These results indicate that weight management in older, nonobese adults may be facilitated by increased dietary CR and decreased susceptibility to hunger with age. Additionally, changes in energy and macronutrient intake may not be necessary for successful weight management with advancing age.

Peripheral ghrelin treatment stabilizes body weights of senescent male Brown Norway rats at baseline and after surgery

Unintentional weight loss may occur spontaneously in older humans and animals. Further weight losses after surgery or illness in the older patients result in increased morbidity, mortality, and hospital readmission rate. A growing body of work has shown increased appetite and weight gain in response to administration of ghrelin, the “hunger hormone.” We conducted two studies in senescent male Brown Norway rats to assess the ability of peripheral administration of ghrelin to increase body weight and food intake. One study assessed the effect of 2 wk of daily subcutaneous ghrelin administration (1 mg·kg−1·day−1) to senescent rats in a baseline condition; a second study used the same administration protocol in an interventional experiment with aged rats subjected to a surgery with 10–15% blood loss as a model of elective surgery. In both studies, animals receiving ghrelin maintained their body weights, whereas control animals lost weight. Body weight stability was achieved in ghrelin-treated animals despite a lack of increase in daily or cumulative food intake in both experiments. Hormone and proinflammatory cytokine levels were measured before surgery and after 14 days of treatment. Ghrelin treatment appeared to blunt declining ghrelin levels and also to blunt cytokine increases seen in the surgical control group. The ability of peripheral ghrelin treatment to maintain body weights of senescent rats without concomitant increases in food intake may be due to its known ability to decrease sympathetic activity and metabolic rate, perhaps by limiting cytokine-driven inflammation.

Dietary variety and its effect on food intake of elderly adults

BACKGROUND

Older people frequently have poor food intake. This present study investigated the effect of dietary variety on food intake in younger and older people.

METHODS

Eighteen young adults (mean age = 26 years) and 18 older adults (mean age = 70 years) consumed four consecutive courses of sandwiches on two occasions. In the plain treatment, each course of sandwiches was of the same type, while in the variety treatment four courses, each of a different type of sandwich, were served. Each time the participants were presented with a serving of sandwiches and asked to eat as much as they liked.

RESULTS

In the plain condition, the older adult group consumed more than their young counterparts. This situation was reversed for the variety condition when the young group ate more than the older adults. Interestingly, the older adult group ate more when a variety of sandwiches was presented. This may be contrary to what is predicted by the sensory-specific satiety model of eating behaviour.

CONCLUSIONS

This study suggests that presenting the older people with a varied meal may be a valid strategy to improve food intake in this group.

Pharmacological Treatment of Geriatric Cachexia: Evidence and Safety in Perspective

Anticachexic or antisarcopenic medications are prescribed worldwide for geriatric patients with poor appetite and associated weight loss. They represent a valuable treatment option for managing cachexia. However, the well-publicized adverse reports about these medications in acquired immunodeficiency syndrome (AIDS) and in the cancer population has led to some concern and much subsequent discussion over the safety of these medications being used in geriatric population. This review looks at the evidence in relation to the benefits and risks of these medications and discusses what we know about their use in the geriatric population.

Eating patterns and dietary composition in relation to BMI in younger and older adults

OBJECTIVE

To compare relative associations of eating patterns and dietary composition with body mass index (BMI) in younger (aged 20-59 years, n=1792) and older (aged 60-90 years, n=893) participants in the Continuing Survey of Food Intakes by Individuals, collected 1994-1996.

METHODS

Data from two 24-h dietary recalls from individuals reporting physiologically plausible energy intake (within +/-22% of predicted energy requirements, based on previously published methods) were used.

RESULTS

Mean reported energy intake was 96 and 95% of predicted energy requirements in younger and older subjects, respectively. Older subjects were less likely than younger subjects to skip a meal, but snacking was common in both age groups. Fiber density was significantly higher in the older group. A higher BMI in both age groups was associated with a higher total daily energy intake, and higher energy intakes at all eating occasions. In both age groups, eating frequency was positively associated with energy intake, and eating more than three times a day was associated with being overweight or obese. In the younger group but not the older group, a lower fiber density coupled with higher percentage of energy from fat was independently associated with having a higher BMI.

CONCLUSIONS

While no one eating occasion contributes more than any other to excess adiposity, eating more often than three times a day may play a role in overweight and obesity in both younger and older persons. A reduced satiety response to dietary fiber in addition to lower energy expenditure may potentially further contribute to weight gain in older persons.

Eating behavior and weight change in healthy postmenopausal women: results of a 4-year longitudinal study

BACKGROUND

The association of psychological eating behavior constructs with overweight and obesity during early adult life and middle age has been documented in several studies. However, the association of eating behavior with unexplained weight change in old age is relatively unexplored.

METHODS

Body weight, eating behavior (dietary restraint, disinhibition, and hunger as assessed by the Eating Inventory), reported dietary intake, and physical activity level were assessed at baseline in 36 nonobese postmenopausal women aged 61.3 +/- 3.1 years (mean +/- standard deviation). Measurements were repeated 4.4 +/- 0.9 years later, and changes in body weight were examined in relation to baseline and follow-up eating behavior scores, reported dietary intake, and physical activity level.

RESULTS

Participants had no major changes in health or lifestyle characteristics over the study interval. Weight change ranged from -7.5 to +5.8 kg (mean -0.3 +/- 3.5 kg), and there were no significant changes in reported dietary intake. Mean hunger score (calculated as the mean of baseline and follow-up hunger score) predicted weight change per year over the study period (bivariate r = 0.386, p =.020), even in statistical models adjusted for mean dietary intake variables (partial r = 0.658, p =.003). Restraint, disinhibition, and physical activity level did not predict weight change.

CONCLUSIONS

Reported hunger assessed by the Eating Inventory was associated with unintentional weight change in healthy postmenopausal women. The Eating Inventory questionnaire may provide a clinically useful tool for identifying older individuals at risk of undesirable weight change, and particularly unintentional weight loss, a factor strongly associated with increased morbidity and premature death in this population.

The anorexia of aging in humans

Energy intake is reduced in older individuals, with several lines of evidence suggesting that both physiological impairment of food intake regulation and non-physiological mechanisms are important. Non-physiological causes of the anorexia of aging include social (e.g. poverty, isolation), psychological (e.g. depression, dementia), medical (e.g. edentulism, dysphagia), and pharmacological factors. Physiological factors include changes in taste and smell, diminished sensory-specific satiety, delayed gastric emptying, altered digestion-related hormone secretion and hormonal responsiveness, as well as food intake-related regulatory impairments for which specific mechanisms remain largely unknown. Studies in healthy elderly individuals have shown that men who consume diets over several weeks providing either too few or too many calories relative to dietary energy needs subsequently do not compensate for the resulting energy deficit or surplus when provided an ad libitum diet. Healthy elders have also been shown to be less hungry at meal initiation and to become more rapidly satiated during a standard meal compared to younger adults. Studies in animal models are required to investigate potential mechanisms underlying these observations, while human studies should focus on examining the potential consequences of this phenomenon and practical therapeutic strategies for the maintenance of appropriate energy intake with increasing age. In light of this need, we have recently demonstrated that low reported hunger assessed using a simple questionnaire predicts unintentional weight loss in a sample of healthy older women, and thus may provide a clinically useful tool for identifying older individuals at risk for undesirable weight change and therefore at high priority for intervention.

Consequences of inadequate food energy and negative energy balance in humans

Energy deficiency is probably best measured in adults by the body mass index (BMI). Acute energy deficiency (AED) is associated with body weight loss, along with changes in body composition, as well as a reduced BMR and physical activity. Chronic energy deficiency (CED) is an inadequacy in food to which individuals adapt, at some cost. Individuals with this have never 'lost' weight: they have simply grown less. They adapt to the decreased food energy by reductions in their total energy expenditure (TEE), linked mainly to a lower body size, and to their physical activity. It seems unlikely that enhanced metabolic efficiency contributes substantially to energy saving in CED. Supplementation of energy deficient individuals is accompanied by significant fat deposition; this may have deleterious consequences. Women in many developing countries achieve a successful outcome to pregnancy in spite of being chronically undernourished. Reductions in basal metabolism and behavioural changes in the form of diminished physical activity could meet most of the extra energy needed for pregnancy. Milk energy output is maintained within the expected range in undernourished lactating mothers. Energy deficiency in children is best measured by height-for-age for stunting, and weight-for-height for wasting. Deficits in behavioural and functional parameters in children exist with undernutrition, and can be reduced by early nutritional supplementation along with the appropriate environment.

Nutrition and Aging: Changes in the Regulation of Energy Metabolism With Aging

Changes in energy regulation occur during normal aging and contribute to the common phenomenon of weight and fat losses late in life. This review synthesizes data on aging-related changes in energy intake and energy expenditure and on the regulation of energy intake and expenditure. The ability of older adults to accurately regulate energy intake is impaired, with a number of possible explanations including delayed rate of absorption of macronutrients secondary to reductions in taste and smell acuity and numerous hormonal and metabolic mediators of energy regulation that change with aging. There are also changes in patterns of dietary intake and a reduction in the variety of foods consumed in old age that are thought to further reduce energy intake. Additionally, all components of energy expenditure decrease with aging, in particular energy expenditure for physical activity and basal metabolic rate, and the ability of energy expenditure to increase or decrease to attenuate energy imbalance during overeating or undereating also decreases. Combined, these changes result in an increased susceptibility to energy imbalance (both positive and negative) in old age that is associated with deteriorations in health. Practical interventions for prevention of weight and fat fluctuations in old age are anticipated here based on emerging knowledge of the role of such factors as dietary variety, taste, and palatability in late-life energy regulation.

Effect of Aging on the Response of Ghrelin to Acute Weight Loss

OBJECTIVES

To determine whether the failure of the orexigenic hormone ghrelin to increase as it normally does with weight loss contributes to impaired weight recovery in older persons.

DESIGN

Prospective diet intervention study.

SETTING

University of Washington Medical Center from 2001 through 2005.

PARTICIPANTS

Twenty-one younger (18-35) and 18 older (> or =70) men and women.

INTERVENTION

Two weeks of a weight-maintaining diet were followed in sequence by 2 weeks of 30% calorie restriction, then 4 weeks of ad libitum food intake.

MEASUREMENTS

Twenty-four-hour plasma ghrelin levels, dual x-ray absorptiometry scan for body composition, resting energy expenditure, and calorie intakes were measured.

RESULTS

Both younger and older subjects lost weight with calorie restriction and failed to fully regain their baseline weight. The older adults trended toward increasing their calorie intake above their baseline level during the ad libitum period (111+/-66 kcal, P=.11), whereas the younger individuals did not (-236+/-95 kcal, P=.02). There was no statistically significant difference between the two cohorts in 24-hour ghrelin levels before or after calorie restriction. Ghrelin levels in the two cohorts increased equivalently after calorie restriction and decreased after ad libitum food consumption resumed.

CONCLUSION

Ghrelin levels in healthy older individuals respond appropriately in a compensatory manner to changes in body weight and calorie intake.

Effects of variation in protein and carbohydrate intake on body mass and composition during energy restriction: a meta-regression 1

BACKGROUND

It is unclear whether low-carbohydrate, high-protein, weight-loss diets benefit body mass and composition beyond energy restriction alone.

OBJECTIVE

The objective was to use meta-regression to determine the effects of variations in protein and carbohydrate intakes on body mass and composition during energy restriction.

DESIGN

English-language studies with a dietary intervention of > or =4200 kJ/d (1000 kcal/d), with a duration of > or =4 wk, and conducted in subjects aged > or =19 y were considered eligible for inclusion. A self-reported intake in conjunction with a biological marker of macronutrient intake was required as a minimum level of dietary control. A total of 87 studies comprising 165 intervention groups met the inclusion criteria.

RESULTS

After control for energy intake, diets consisting of < or =35-41.4% energy from carbohydrate were associated with a 1.74 kg greater loss of body mass, a 0.69 kg greater loss of fat-free mass, a 1.29% greater loss in percentage body fat, and a 2.05 kg greater loss of fat mass than were diets with a higher percentage of energy from carbohydrate. In studies that were conducted for >12 wk, these differences increased to 6.56 kg, 1.74 kg, 3.55%, and 5.57 kg, respectively. Protein intakes of >1.05 g/kg were associated with 0.60 kg additional fat-free mass retention compared with diets with protein intakes < or =1.05 g/kg. In studies conducted for >12 wk, this difference increased to 1.21 kg. No significant effects of protein intake on loss of either body mass or fat mass were observed.

CONCLUSION

Low-carbohydrate, high-protein diets favorably affect body mass and composition independent of energy intake, which in part supports the proposed metabolic advantage of these diets.

Effects of hypothalamic neurodegeneration on energy balance

Normal aging in humans and rodents is accompanied by a progressive increase in adiposity. To investigate the role of hypothalamic neuronal circuits in this process, we used a Cre-lox strategy to create mice with specific and progressive degeneration of hypothalamic neurons that express agouti-related protein (Agrp) or proopiomelanocortin (Pomc), neuropeptides that promote positive or negative energy balance, respectively, through their opposing effects on melanocortin receptor signaling. In previous studies, Pomc mutant mice became obese, but Agrp mutant mice were surprisingly normal, suggesting potential compensation by neuronal circuits or genetic redundancy. Here we find that Pomc-ablation mice develop obesity similar to that described for Pomc knockout mice, but also exhibit defects in compensatory hyperphagia similar to what occurs during normal aging. Agrp-ablation female mice exhibit reduced adiposity with normal compensatory hyperphagia, while animals ablated for both Pomc and Agrp neurons exhibit an additive interaction phenotype. These findings provide new insight into the roles of hypothalamic neurons in energy balance regulation, and provide a model for understanding defects in human energy balance associated with neurodegeneration and aging.

Mice are genetically engineered for the progressive degeneration of hypothalamic neurons containing the neuropeptides Pomc and Agrp. Their phenotypes suggest a model for energy balance changes associated with aging.

Short-term weight changes in community-dwelling older adults: the Health, Aging, and Body Composition Weight Change Substudy

BACKGROUND

The frequency and short-term natural history of weight loss in community-dwelling older adults have not been described. Unintentional weight loss may be more likely to continue than intentional weight loss.

OBJECTIVES

The present substudy described the frequency of a > or = 5% loss or gain in body weight in community-dwelling older adults at an annual examination of the Health, Aging, and Body Composition (Health ABC) Study and 6 mo later. The weight-management practices used by the participants were also described.

DESIGN

A total of 522 older adults with either a > or = 5% weight gain (n = 116) or a > or = 5% weight loss (n = 171) in the previous year were compared with a random sample of weight-stable older adults (< 5% weight loss or gain, n = 235) at the fourth annual visit of the ongoing Health ABC Study. The participants' weight-loss intention and weight-management practices were assessed by an interview. The participants' weight was reassessed 6 mo later.

RESULTS

Compared with the weight-stable participants, the participants who had lost or gained weight at the substudy baseline were more likely to have subsequent weight changes. The direction of the subsequent weight change, however, was more likely toward either maintenance of or recovery from the previous weight change. Only 4% of the participants who gained weight and 11% of those who lost weight continued to gain or lose weight, respectively. Continued weight loss was more common in the participants with unintentional weight loss than in those with intentional weight loss, but the difference was not significant.

CONCLUSIONS

Weight changes were common, but most participants, including those who unintentionally lost weight, maintained their weight change or resolved their weight change in 6 mo. Unintentional weight loss appears less likely to resolve than other weight changes.

Dietary variety predicts low body mass index and inadequate macronutrient and micronutrient intakes in community-dwelling older adults

BACKGROUND

Low body mass index (BMI) and micronutrient deficiencies are associated with increased morbidity and mortality rates in old age. Whether adverse patterns of dietary variety predict both low BMI and low micronutrient intakes in older adults was investigated.

METHODS

A cross-sectional analysis of national survey data was conducted in 1174 healthy adult men and women (ages 21 to 90 years) who provided physiologically plausible dietary data in the 1994-1996 Continuing Survey of Food Intakes by Individuals. Measurements included reported energy intake, protein intake (percentage meeting Recommended Dietary Allowance), micronutrient intakes (percentage meeting Estimated Average Requirements for 14 micronutrients), and BMI.

RESULTS

Adults who were 61 years or older consumed a greater total variety of foods, chose foods from a wider range of food groups, had a greater variety of micronutrient-dense foods and energy-weak foods, and had a lower variety of micronutrient-weak foods compared with adults ages 21 to 60 years (p < .05 to.001). However, older adults with low BMIs (< 22 kg/m2) consumed a lower variety of energy-dense foods compared with older adults with higher BMIs (p < .05). The variety of energy-dense foods predicted both energy intake and BMI at all ages in multiple regression models controlling for confounding variables (R2 = .124 for energy, R2 = .574 for BMI, p < .001). A higher percentage of older persons had inadequate micronutrient intakes compared with younger persons (p < .05), especially vitamin E, calcium, and magnesium, but consumption of a particularly wide variety of micronutrient-rich foods helped counterbalance these trends (p < .05). Older adults who had a low BMI and consumed a low variety of micronutrient-dense foods were particularly at nutritional risk, with only 65.4% consuming the Recommended Dietary Allowance for protein and none meeting the Estimated Average Requirements for all 14 micronutrients.

CONCLUSIONS

In contrast to previous suggestions that older persons consume a monotonous diet, this study showed that adults who were 61 years or older consumed a greater total food variety, and a greater variety of micronutrient-dense and energy-weak foods, compared with adults who were 60 years or younger. Although consumption of a low variety of energy-dense foods may contribute to reduced energy intake and body weight at any age, the variety of micronutrient-dense foods consumed needs to increase in old age to prevent micronutrient deficiencies. These findings suggest that all adults need advice on the changing needs for dietary variety with aging to maintain health, and that older persons with low BMI are particularly vulnerable to dietary shortfalls.

Providing nutrition supplements to institutionalized seniors with probable Alzheimer's disease is least beneficial to those with low body weight status

OBJECTIVES

To examine whether providing a midmorning nutrition supplement increases habitual energy intake in seniors with probable Alzheimer's disease (AD) and to investigate the effects of body weight status and cognitive and behavioral function on the response to the intervention.

DESIGN

Randomized, crossover, nonblinded clinical trial.

SETTING

A fully accredited geriatric teaching facility affiliated with the University of Toronto's Medical School with a home for the aged.

PARTICIPANTS

Thirty-four institutionalized seniors with probable AD who ate independently.

INTERVENTION

Nutrition supplements were provided between breakfast and lunch for 21 consecutive days and compared with 21 consecutive days of habitual intake.

MEASUREMENTS

Investigator-weighed food intake, body weight, cognitive function (Severe Impairment Battery and Global Deterioration Scale), behavioral disturbances (Neuropsychiatric Inventory-Nursing Home Version), and behavioral function (London Psychogeriatric Rating Scale).

RESULTS

Relative to habitual intake, group mean analyses showed increased 24-hour energy, protein, and carbohydrate intake during the supplement phase, but five of 31 subjects who finished all study phases completely compensated for the energy provided by the supplement by reducing lunch intake, and 24-hour energy intake was enhanced in only 21 of 31 subjects. Compensation at lunch was more likely in subjects with lower body mass indices, increased aberrant motor behavior, poorer attention, and increased mental disorganization/confusion.

CONCLUSION

Nutrition supplements were least likely to enhance habitual energy intake in subjects who would normally be targeted for nutrition intervention-those with low body weight status. Those likely to benefit include those with higher body mass indices, less aberrant motor problems, less mental disorganization, and increased attention.

Obesity over the life course

Obesity in middle-aged humans is a risk factor for many age-related diseases and decreases life expectancy by about 7 years, which is roughly comparable to the combined effect of all cardiovascular disease and cancer on life span. The prevalence of obesity increases up until late middle age and decreases thereafter. Mechanisms that lead to increased obesity with age are not yet well understood, but current evidence implicates impairments in hypothalamic function, especially impairments in the ability of hypothalamic pro-opiomelanocortin neurons to sense nutritional signals. The rapid increase in the prevalence of obesity at all ages in the past decade suggests that, in the next two or three decades, diseases associated with obesity, especially diabetes, will begin to rise rapidly. Indeed, these trends suggest that for the first time in modern history, the life expectancy of people in developed societies will begin to decrease, unless the rapid increase in the prevalence of obesity can be reversed.

Restricting fluid intake during a single meal did not affect food intake in older adults

Restricting fluid intake has been shown to decrease ad libitum food intake in animals and young adult humans. The purpose of this study was to determine if restricting fluid intake during a meal affects food intake in older adults. In a crossover counterbalanced design, 24 subjects (11 m, 13 f), 61-95 years, received lunch at a congregate meal site. Identical meals were accompanied by a volume of water equal to either 40% (restricted) or 100% (control) of each subject's usual lunch fluid intake. Pre-meal urine osmolality and specific gravity were used as indicators of hydration status. Weighed food intake was not different between the restricted and control conditions (400 g/2875 kJ and 408 g/2971 kJ, respectively). No significant correlations were found between urine osmolality or specific gravity and food intake, either in response to fluid restriction or per kg body weight. These results suggest that the appetite of healthy free-living older adults is not affected by fluid restriction during a single eating episode.

Food intake in the real world: implications for nutrition and aging

Nutrient intakes are affected by two classes of factors, physiological and environmental. In the real world, environmental variables such as social factors, palatability, and the time of eating appear to have large influences on amounts ingested in the short-term. Physiological control mechanisms also operate to regulate intake, and they induce compensatory responses to deviations from the norm. These physiological influences only appear to have weak influences on short-term intake unless there are large deviations from the normal state, but over the long-term they act patiently and persistently to rectify the excesses produced by environmental fluctuations and thereby tend to maintain a relative balance between energy intake and expenditure. As individuals age there is a progressive decline in physiological function including the mechanisms that act to control intake in the young. This should not produce a problem in a healthy individual in a stable environment: however, if that situation should change due to illness or an environmental change such as the death of a spouse, which produces decline in intake, elderly individuals would not have the physiological mechanisms present to compensate. Thus, the deficit in energy intake would not be replaced, and the lower level of intake would be maintained as long as the new health condition or environment remains stable. Hence, the decline in the effectiveness of the physiological systems with age makes the elderly particularly vulnerable and unable to rebound from deficits. Although the elderly have difficulty compensating for deficits automatically by physiologically-induced adjustments, the studies of real world intake reviewed in this article suggest that compensation can be produced by adjustments to the environment. The elderly appear to be as responsive to environmental factors as younger individuals. In particular, they appear to increase intake in response to social facilitation, diurnal rhythms, the eating environment, and palatability to the same extent as their juniors. These data suggest that alterations in the social, temporal, environmental, or hedonic conditions of eating could induce desired alterations in the nutrient intakes of the elderly. The study of real world eating behavior has produced evidence that suggests that this strategy can work. It remains for future applied investigations to ascertain whether or not this strategy is effective in treating undernutrition in the elderly.

An underfeeding study in healthy men and women provides further evidence of impaired regulation of energy expenditure in old age

The effect of aging on energy regulation remains controversial. We compared the effects of underfeeding on changes in energy expenditure and respiratory quotient in young normal weight men and women [YNW, age 25.7 +/- 3.2 y(SD), body mass index (BMI) 23.1 +/- 1.6 kg/m(2)], young overweight men and women (YOW, age 26.1 +/- 3.5 y, BMI 27.7 +/- 2.1 kg/m(2)) and older (OLD) men and women (age 68.4 +/- 3.3 y, BMI 27.4 +/- 3.4 kg/m(2)). The thermic effect of feeding (TEF) during weight maintenance, and changes in resting energy expenditure (REE) and respiratory quotient were determined in response to undereating by an average 3.75 MJ/d for 6 wk. In addition, body composition was measured. No significant differences among the groups were observed in TEF, fasting and postprandial respiratory quotient, or the change in fasting respiratory quotient with underfeeding. However, REE adjusted for fat-free mass and fat mass was significantly lower in OLD subjects compared with YNW and YOW subjects (P < 0.05). In addition, the REE response to weight change was significantly attenuated in the OLD subjects (P = 0.023). These data suggest that the responsiveness of energy expenditure to negative energy balance is attenuated in old age, and provide further support for the hypothesis that mechanisms of energy regulation are broadly disregulated in old age.