Commercial weight loss diets meet nutrient requirements in free living adults over 8 weeks: a randomised controlled weight loss trial

The impact of weight loss diet programs on anemia, nutrient deficiencies, and organ dysfunction markers among university female students: A cross-sectional study

Practicing restricted weight loss diet programs (WLDPs) without proper supervision can result in nutritional deficiency, which can lead to the development of several nutritional disorders. The current cross-sectional study aimed to investigate the impact of WLDPs practiced by university female students on the prevalence of micronutrient deficiencies, anemia, and organs dysfunction, and to assess the association of identified anomalies with dieting practices and dietary habits of university female students. A total of 185 (105 dieting and 80 non-dieting) volunteers’ female students at Al-Hussein Bin Talal University participated in this study. After the participants answered a questionnaire, blood samples were collected for hematological and biochemical analysis, and the body mass index (BMI) was determined. The results show that there were no significant differences between dieting and non-dieting groups in biochemical markers of kidney and liver functions as well as serum levels of copper, zinc, and folate. On the other hand, dieting participants exhibited significantly lower level of hemoglobin, serum ferritin, iron, and vitamin B12 than encounter group (p<0.05). Attempting WLDPs significantly increased the prevalence of anemia (46.7%), iron deficiency (57.1%), and iron deficiency anemia (IDA) (41.9%), comparing to non-dieting students (28.7%, 33.8%, and 15.0%, respectively) (p<0.005). Chi-square test showed that the development of anemia among dieting girls was significantly dependence of several factors including BMI category, source and duration of the diet programs, and skipping breakfast (p<0.05). In conclusion, young girls attempting WLDPs without professional guidance are more prone to the risk of nutrients deficiencies and the development nutritional disorders like IDA. An educational program should be employed to teach young females on when and how to adopt healthy WLDPs.

Low and reduced carbohydrate diets: challenges and opportunities for type 2 diabetes management and prevention

Low-carbohydrate diets (LCD) have been promoted for weight control and type 2 diabetes (T2D) management, based on an emerging body of evidence, including meta-analyses with an indication of publication bias. Proposed definitions vary between 50 and 130 g/d, or <10 and <40 % of energy from carbohydrate, with no consensus on LCD compositional criteria. LCD are usually followed with limited consideration for other macronutrients in the overall diet composition, introducing variance in the constituent foods and in metabolic responses. For weight management, extensive evidence supports LCD as a valid weight loss treatment, up to 1-2 years. Solely lowering carbohydrate intake does not, in the medium/long term, reduce HbA1c for T2D prevention or treatment, as many mechanisms interplay. Under controlled feeding conditions, LCD are not physiologically or clinically superior to diets with higher carbohydrates for weight-loss, fat loss, energy expenditure or glycaemic outcomes; indeed, all metabolic improvements require weight loss. Long-term evidence also links the LCD pattern to increased CVD risks and mortality. LCD can lead to micronutrient deficiencies and increased LDL-cholesterol, depending on food selection to replace carbohydrates. Evidence is limited but promising regarding food choices/sources to replace high-carbohydrate foods that may alleviate the negative effects of LCD, demanding further insight into the dietary practice of medium to long term LCD followers. Long-term, high-quality studies of LCD with different food sources (animal and/or plant origins) are needed, aiming for clinical endpoints (T2D incidence and remission, cardiovascular events, mortality). Ensuring micronutrient adequacy by food selection or supplementation should be considered for people who wish to pursue long-term LCD.

Application of nutrient essentiality criteria to dietary carbohydrates

The purpose of the present review is to describe how human physiology at very low carbohydrate intakes relates to the criteria for nutritional essentiality. Although we did not limit ourselves to one particular type or function of carbohydrates, we did primarily focus on glucose utilisation as that function was used to determine the recommended daily allowance. In the general population, the human body is able to endogenously synthesise carbohydrates, and does not show signs of deficiency in the absence of dietary carbohydrates. However, in certain genetic defects, such as glycogen storage disease type I, absence of dietary carbohydrates causes abnormalities that are resolved with dietary supplementation of carbohydrates. Therefore, dietary carbohydrates may be defined as conditionally essential nutrients because they are nutrients that are not required in the diet for the general population but are required for specific subpopulations. Ketosis may be considered a physiological normal state due to its occurrence in infants in addition to at very low carbohydrate intakes. Although sources of dietary carbohydrates can provide beneficial micronutrients, no signs of micronutrient deficiencies have been reported in clinical trials of low-carbohydrate ketogenic diets. Nonetheless, more research is needed on how micronutrient requirements can change depending on the dietary and metabolic context. More research is also needed on the role of dietary fibre during a low-carbohydrate ketogenic diet as the beneficial effects of dietary fibre were determined on a standard diet and several studies have shown beneficial effects of decreasing non-digestible carbohydrates.

Diet Quality and Micronutrient Intake among Long-Term Weight Loss Maintainers

Inadequate vitamin and mineral intake is documented among individuals with obesity, but is unknown among long-term weight loss maintainers (WLM). This study examined dietary quality and micronutrient adequacy among WLMs in a commercial weight management program. Participants were 1207 WLM in Weight Watchers (WW) who had maintained a 9.1 kg or greater weight loss (29.7 kg on average) for 3.4 years and had a body mass index (BMI) of 28.3 kg/m². A control group of weight stable adults with obesity (controls; N = 102) had a BMI of 41.1 kg/m². Measures included the Diet History Questionnaire-II, Healthy Eating Index-2015 (HEI), and Dietary References Intakes. WLM versus controls had a 10.1 point higher HEI score (70.2 (69.7–70.7) vs. 60.1 (58.4–61.8); p = 0.0001) and greater odds of meeting recommendations for copper (OR = 5.8 (2.6–13.1)), magnesium (OR = 2.9 (1.8–4.7)), potassium (OR = 4.7 (1.4–16.5)), vitamin A (OR = 2.8 (1.7–4.8)), vitamin B6 (OR = 2.9 (1.6–5.2)), and vitamin C (OR = 5.0 (2.8–8.8)). WLM, compared to controls, also reported higher percentages of calories from carbohydrates (50.3% (49.7–50.8) vs. 46.7% (44.8–48.7); p = 0.0001) and protein (18.2% (18.0–18.5) vs. 15.9% (15.1–16.6); p = 0.0001) and lower calories from fat (32.3% (31.9–32.8) vs. 37.4% (35.8–38.9); p = 0.0001). Long-term weight loss maintenance in a widely used commercial program was associated with a healthier diet pattern, including consuming foods with higher micronutrient density.

Impacts of carbohydrate-restricted diets on micronutrient intakes and status: A systematic review

A systematic review of published evidence on micronutrient intake/status with carbohydrate-restricted diets (CRD) was conducted in Web of Science, Medline, Embase, Scopus, CENTRAL, and ClinicalTrials.gov up to October 2018. We identified 10 studies: seven randomized controlled trials (RCTs) ("Atkins"-style, n = 5; "Paleolithic" diets, n = 2), two Atkins-style noncontrolled trials and one cross-sectional study. Prescribed carbohydrate varied 4% to 34% of energy intake. Only one noncontrolled trial prescribed multivitamin supplements. Dietary intakes/status were reported over 2 to 104 weeks, with weight losses from 2 to 9 kg. No diagnoses of deficiency were reported. Intakes of thiamine, folate, magnesium, calcium, iron, and iodine all decreased significantly (-10% to -70% from baseline) with any CRD types. Atkins diet trials (n = 6; 4%-34%E carbohydrate) showed inconsistent changes in vitamin A, E, and β-carotene intakes, while a single "Paleolithic" diet trial (28%E carbohydrate) reported increases in these micronutrients. One other "Paleolithic" diet (30%E carbohydrate) reported a rise in moderate iodine deficiency from 15% to 73% after 6 months. In conclusion, few studies have assessed the impacts of CRD on micronutrients. Studies with different designs point towards reductions in several vitamins and minerals, with potential risk of micronutrient inadequacies. Trial reporting standards are expected to include analysis of micronutrient intake/status. Micronutrients in foods and/or supplements should be considered when designing, prescribing or following CRDs.

Nutrient Intake During Diet-Induced Weight Loss and Exercise Interventions in a Randomized Trial in Older Overweight and Obese Adults

OBJECTIVES

Dietary restriction in obese older adults undergoing weight loss may exacerbate nutrient deficiencies common in this group; the nutritional health of older adults is a factor in their quality of life, disability, and mortality. This study examined the effect of an 18-month weight loss program based in social cognitive theory incorporating partial meal replacements, on nutrient intake in older overweight and obese adults.

DESIGN

The following analysis is from the Intensive Diet and Exercise for Arthritis (IDEA) trial, a single-blind, randomized controlled trial. Individuals were randomized into one of three 18-month interventions: exercise (E); intensive diet-induced weight loss (D); or intensive diet-induced weight loss plus exercise (D+E).

SETTING

The study setting was at a university research facility.

PARTICIPANTS

Overweight and obese older adults (n=388; BMI=33.7±3.8 kg/m2; 65.8±6.1 years) were recruited.

INTERVENTIONS

The D and D+E interventions (group mean goal of ≥10% loss by 18-months) utilized partial meal replacements (2 meal replacement shakes/day for 6-months). Exercise training for E and D+E was 3 days/week, 60 minutes/day.

MEASUREMENTS

Three day food records were collected at baseline, 6-months, and 18-months and analyzed for total energy and macro- and micronutrient intake. Comparisons of dietary intake among treatment groups were performed at 6 and 18 months using mixed linear models.

RESULTS

Weight loss at 18-months was 11.3±8.3% (D), 10.3±6.8% (D+E), and 1.2±4.2% (E). Meal replacements were used by more than 60% (6-months) and 50% (18-months) of D and D+E participants, compared to ≤15% for E. Both D and D+E consumed less energy and fat, and more carbohydrates and selected micronutrients than E during follow-up. More than 50% of all participants consumed less than the recommended intake of particular vitamins and minerals.

CONCLUSIONS

The diet intervention improved intakes of several nutrients. However, inadequate intake of several vitamins and minerals of concern for older adults suggests they need further guidance to assure adequate intake.

Changes of dietary patterns during participation in a web-based weight-reduction programme

Objective

To examine the weight-loss success associated with distinct dietary patterns and to determine changes of these dietary patterns during participation in a web-based weight-reduction programme.

Design

Factor analysis was used to identify the dietary patterns of twenty-two food groups that were administered in 14 d dietary protocols at baseline and after 3 months. Successful weight loss (≥5 % of initial weight) and BMI were calculated. Logistic regression analyses were used to assess the rates of weight-loss success from each dietary pattern and changing or remaining in the initial dietary pattern. A generalised linear mixed model was used to estimate the effects of changing or staying in a dietary pattern on change in BMI.

Subjects

Adults (n 1635) aged 18–81 years.

Setting

Users of a web-based weight-reduction programme (2006–2012).

Results

Participants who aligned to a healthful dietary pattern at baseline (OR=1·8; 95 % CI 1·5, 2·3) and after 3 months (OR=1·5; 95 % CI 1·2, 1·9) had a greater chance of successfully losing weight. After adjusting for age, sex, initial dietary pattern and BMI, participants who started with or changed to the healthful dietary pattern had a greater chance of being successful (OR=1·4; 95 % CI 1·1, 1·7) and a higher BMI reduction of 0·30 (95 % CI 0·2, 0·5) kg/m2 compared with those who started with or changed to the energy-dense or high-carbohydrate dietary pattern.

Conclusions

A favourable healthful dietary pattern at the beginning and after 3 months was positively associated with anthropometry. However, successful weight loss was feasible in each dietary pattern.

Sex differences in the composition of weight gain and loss in overweight and obese adults

Sex differences in the ratio of fat mass (FM):fat-free mass (FFM) during weight change should differentially affect the extent of weight change during energy imbalance in men and women. In the present study, we determined FM and FFM contents by dual-energy X-ray absorptiometry and calculated the P-ratios (protein energy/total energy) of excess weight and weight loss during a randomised controlled trial of four commercial weight loss regimens. Overweight and obese women (n 210) and men (n 77) were studied at baseline and at 2 and 6 months during weight loss on four dietary regimens: Dr Atkins' New Diet Revolution; The Slim-Fast Plan; Weight-Watchers programme; Rosemary Conley's Diet and Fitness Plan. At baseline, the percentage of FFM (%FFM) and P-ratios of excess weight were 40 % and 0·071 for men and 27 % and 0·039 for women. At 2 months, men had lost twice as much weight as women and three times more FFM than women, indicating higher FFM content and P-ratios of weight loss for men, 0·052, than for women, 0·029, with no dietary effects. Between 2 and 6 months, the rate at which weight was lost decreased and the %FFM of weight loss decreased to similar low levels in men (7 %) and women (5 %): i.e. P-ratios of 0·009 and 0·006, respectively, with no dietary effects. Thus, for men compared with women, there were greater FFM content and P-ratios of weight change, which could partly, but not completely, explain their greater weight loss at 2 months. However, protein-conserving adaptations occur with increasing weight loss and over time, more extensively in men, eventually eliminating any sex difference in the composition of weight loss.

Nutrient deficiencies after gastric bypass surgery

Bariatric surgery, and in particular, gastric bypass, is an increasingly utilized and successful approach for long-term treatment of obesity and amelioration of comorbidities. Nutrient deficiencies after surgery are common and have multiple causes. Preoperative factors include obesity, which appears to be associated with risk for several nutrient deficiencies, and preoperative weight loss. Postoperatively, reduced food intake, suboptimal dietary quality, altered digestion and absorption, and nonadherence with supplementation regimens contribute to risk of deficiency. The most common clinically relevant micronutrient deficiencies after gastric bypass include thiamine, vitamin B₁₂, vitamin D, iron, and copper. Reports of deficiencies of many other nutrients, some with severe clinical manifestations, are relatively sporadic. Diet and multivitamin use are unlikely to consistently prevent deficiency, thus supplementation with additional specific nutrients is often needed. Though optimal supplement regimens are not yet defined, most micronutrient deficiencies after gastric bypass currently can be prevented or treated by appropriate supplementation.

Weight-loss-associated changes in bone mineral density and bone turnover after partial weight regain with or without aerobic exercise in obese women

Background/Objectives

Moderate, long-term weight loss results in loss of bone mass in overweight or obese premenopausal women. However, whether these changes persist during weight maintenance or regain remains to be determined.

Subjects/Methods

Overweight or obese (BMI: 25.8–42.5 kg/m²) women (n=40) with at least two risk factors for the metabolic syndrome participated in this 12-mo study that examined the effects of prescribed weight loss and regain, with or without exercise, on bone turnover and on bone mineral density (BMD) in a subset of participants (n=24). During the first 6 mo, participants lost ~10% of their initial body weight via energy restriction and supervised aerobic exercise. Following weight loss, participants were randomly assigned to either an exercise or a no-exercise treatment for the regain (+50% of weight lost) phase. A one-way (time) repeated measures ANOVA tested the effects of weight loss on BMD and bone turnover, and a two-way RM ANOVA (time, exercise) was used to examine the effects of exercise during weight regain.

Results

Hip (p=0.007) and lumbar spine (p=0.05) BMD decreased with weight loss, and remained reduced after weight regain with or without exercise. Likewise, the weight-loss-associated increases in osteocalcin (p<0.001) and C-terminal peptide of type I collagen (p<0.001) persisted following weight regain, independent of exercise.

Conclusions

the results of the present study, which is the first to examine changes in bone mass and turnover during carefully controlled weight regain, suggest that weight-loss-induced perturbations in bone mass and turnover persist after partial weight regain, regardless of whether regular, weight-bearing aerobic exercise was continued.

The association between weight loss and engagement with a web-based food and exercise diary in a commercial weight loss programme: a retrospective analysis

BACKGROUND

The Internet provides a widely accessible platform for weight loss interventions. Automated tools can allow self-guided monitoring of food intake and other target behaviours that are established correlates of weight change. Many programmes also offer social support from the virtual community. The aim of this research was to assess associations between engagement with self-monitoring tools and social support, and weight loss in an online weight-control programme.

METHODS

This paper describes a retrospective analysis of weight change among 3621 subscribers to a commercial Internet-based weight loss programme. Participants were all subscribers (2979 women; 642 men) joining the programme between July 2005 and November 2008 with two or more recorded weights spanning at least 28 days of participation in the programme. Engagement was indexed with frequency of using online diet and exercise diaries and with use of the social support forums.

RESULTS

Programme engagement was associated with weight loss in both men and women after controlling for initial BMI and duration of participation. The three engagement variables accounted for 13% of variance in percentage weight loss in women (p < .001) and 19% in men (p < .001). In analyses including all the engagement variables, exercise diary use was an independent predictor of weight loss among men, but non-significant in women. In contrast, use of the online forums was associated with weight loss in women but not in men. Among participants who were overweight or obese, those in the highest tertile of engagement with food diaries (vs the lowest) were more likely to achieve clinically significant (> 5%) weight loss (men: OR = 3.45 p < .001; women: OR = 5.05 p < .001). Being in the highest tertile of engagement with exercise diaries was associated with clinically significant weight loss in men (OR = 3.48 p < .001) and, less strongly, in women (OR = 1.46 p < .05).

CONCLUSIONS

Use of self-monitoring tools and participation in online support are predictive of weight loss in the context of a commercial, online weight control programme.

Galactose promotes fat mobilization in obese lactating and nonlactating women

BACKGROUND

Galactose consumption as the only carbohydrate source results in little increase in plasma glucose and insulin concentrations when compared with fasting. Lower insulin might promote endogenous lipolysis during meal absorption, which may facilitate fat loss.

OBJECTIVE

The objective was to test the hypothesis that consumption of an isocaloric, isonitrogenous galactose drink will result in higher rates of lipolysis and fat oxidation than consumption of a glucose drink in obese lactating and nonlactating women.

DESIGN

Seven healthy, obese, exclusively breastfeeding women and 7 healthy, obese, nonlactating women were studied on 2 occasions according to a randomized, crossover, single-blinded design. Subjects received drinks providing ≈70% of the daily estimated energy requirement, of which 60% was either glucose or galactose. The primary outcomes were the rate of appearance (Ra) of glycerol and palmitate, and the secondary outcomes were glucose Ra, milk production, energy expenditure, and substrate oxidation.

RESULTS

Plasma glucose and insulin concentrations were lower (P < 0.05) and those of glycerol, palmitate, free fatty acids, and triglycerides were higher (P < 0.05) during galactose than during glucose feeding in both nonlactating and lactating women. During galactose feeding, glucose Ra was lower (P < 0.01) and glycerol, palmitate, and free fatty acid Ra were higher (P < 0.01) in both groups. During galactose feeding in all women combined, fat oxidation was higher (P = 0.01) and protein oxidation was lower (P < 0.01). Milk production, energy expenditure, and carbohydrate oxidation were similar between glucose and galactose feeding.

CONCLUSIONS

Galactose consumption is associated with higher endogenous fat mobilization and oxidation during meal absorption. Long-term studies are required to determine whether galactose as an exclusive carbohydrate source would promote body fat loss in obese subjects.

Weight management using a meal replacement strategy in type 2 diabetes

The growing prevalence of diabetes parallels the increased prevalence of obesity. Overweight and obese individuals with diabetes who attempt weight reduction face considerable challenges. However, several recent studies showed that weight reduction in patients with diabetes is feasible using a multidisciplinary approach that incorporates structured dietary intervention and meal replacements (MRs). Nutritionally complete MRs are shown to be useful at the start of weight reduction programs and for weight maintenance because of their nutrition adequacy. However, patients using this approach need to monitor their blood glucose levels closely and may need to adjust their diabetes medications. Most commercial MRs are currently fortified with vitamins and minerals to prevent long-term deficiency in essential micronutrients that are commonly seen in low-calorie diet plans. They also come in different flavors and formats that improve their general acceptability. To successfully initiate weight loss, MRs are generally used as absolute replacement of an agreed upon number of meals/snacks. This article covers the use of MRs for patients with diabetes for short-term and long-term weight reduction in clinical trials and real-world clinical practice.