Obese individuals do not underreport dietary intake to a greater extent than nonobese individuals when data are allometrically‐scaled

Genotypic Variations Associated with Changes in Body Mass in Response to Endurance Training

This study investigates the extent to which different genotypes can explain changes in body mass following an 8-week running program, in a UK population. Participants were randomly assigned to either a training (n = 17) or control group (n = 21). Participants' diets were not altered, only the exercise regime was manipulated to isolate effects. The exercise group completed a periodized running program consisting of 20-30 min, over an agreed route, three times per-week, whilst the control groups refrained from daily exercise. Participants were screened at the end of the study for 1,000 gene variants using a DNA test kit. Results demonstrated a significant reduction in body mass, within the exercise, compared to the control group (p = .002). This reduction in body mass varied significantly (p = .024) between individuals within the exercise group. Moreover, genetic analysis identified 17 single nucleotide polymorphisms (SNPs) associated with this variation (r2 = .74; p < .001). These findings indicate that individuals with specific alleles are better predisposed to weight-management, compared to their counterparts, following an exercise program. This study helps to bridge the gap between population health and exercise science and can inform research in the application of genetics to help develop individually tailored health interventions.

Reliability of the Metabolic Response During Steady-State Exercise at FATmax in Young Men with Obesity

Purpose: In this study we evaluated the reliability of blood lactate levels (BLa), energy expenditure and substrate utilization during prolonged exercise at the intensity that elicits maximal fat oxidation (FATmax). Furthermore, we investigated the accuracy of a single graded exercise test (GXT) for predicting energy metabolism at FATmax. Methods: Seventeen young men with obesity (26 ± 6 years; 36.4 ± 7.2 %body fat) performed a GXT on a treadmill in a fasted state (10-12 h) for the assessment of FATmax and cardiorespiratory fitness. Afterward, each subject performed two additional prolonged FATmax trials (102 ± 11 beats·min-1; 60-min) separated by 7 days. Indirect calorimetry was used for the assessment of energy expenditure and substrate utilization kinetics whereas capillary blood samples were taken for the measurement of BLa. Results: The BLa (limits of agreement (LoA): -1.2 to 0.8 mmol∙L-1; p = 1.0), fat utilization (LoA: -8.0 to 13.4 g∙h-1; p = 0.06), and carbohydrate utilization (LoA: -27.6 to 22.4 g∙h-1; p = 0.41) showed a good agreement whereas a modest systematic bias was found for energy expenditure (LoA: -16811 to 33355 kJ∙h-1; p < 0.05). All the aforementioned parameters showed a moderate to good reliability (Intraclass correlation coefficient: 0.67-0.92). The GXT overestimated fat (~46%) and carbohydrate (~26%) utilization as well as energy expenditure (36%) during steady-state exercise at FATmax. Conversely the GXT underestimated BLa (~28%). Conclusion: a single GXT cannot be used for an accurate prediction of energy metabolism during prolonged exercise in men with obesity. Thus, an additional steady-state FATmax trial (40-60 min) should be performed for a tailored and precise exercise prescription.

Pulmonary rehabilitation: A cohort study assessing the effectiveness of a multi-professional nutrition intervention

BACKGROUND

Limited benefit of pulmonary exercise rehabilitation has been associated with fulfilment of energy and protein requirements.

OBJECTIVES

The aim was to enhance dietary intake towards requirements and to maintain changes after a pulmonary rehabilitation program.

METHODS

This single arm intervention study included multidisciplinary focus on nutrition and three sessions of individual dietary counselling during a 10-week pulmonary exercise rehabilitation in five municipalities centers. Data were collected at baseline (P0), at the end of intervention (P1) and for two municipalities at three months post intervention (P2).

RESULTS

Of the 111 included participants, (mean age 70.8 (±9)) 99 (89%) completed the rehabilitation including the three individual dietary counselling's. A very large variation in body composition including body mass index and exercise abilities was found. Protein intake improved from 64 (±22 g) (P0) to 88 (±25 g) (P1) (p < 0.001) and energy intake from 1676 (±505 kcal) (P0) to 1941 (±553 kcal) (p < 0.001) (P1) and Muscle Mass Index increased from 10.6 (±3.2) (P0) to 10.9 (±3.2) (P1) (p = 0.007); number of 30 s chair stand test improved from 10.9 (±2.8) repetitions (P0) to 14.1 (±4.3) repetitions (P1) (p < 0.001), distance in six-minut walking test improved from 377.2 (±131.2 m) (P0) to 404.1 (±128.6 m) (P1) (p < 0.001). Two municipalities completed the three months follow-up. For those, dietary improvements remained stable, including protein intake.

CONCLUSION

Including three sessions of dietary counselling in a multi-professional effort was associated with improved individualized dietary intake, as well as physical function. Benefits remained almost unchanged after three months. Improvements in function could not be fully explained by improved intakes.

Representation of adults with class III obesity in studies assessing validity of self-reported energy intake using doubly labeled water: A systematic review

The measurement of habitual energy intake remains a challenge in nutrition research. High levels of misreporting, particularly among adults with obesity, have been observed when comparing self-reported energy intake to energy expenditure assessed via the doubly labeled water technique. Little is known about misreporting in adults with class III obesity (body mass index ≥40 kg/m2). This systematic review assessed the representation of adults with class III obesity in dietary validation studies and the validity of self-reported dietary energy intake for this group. Studies were included in this review if they: compared self-reported energy intake assessment method(s) to doubly labeled water, had participants ≥18 years old, and included participants with class III obesity. Fifteen studies met these criteria. Of those, eight included information about the number of participants with class III obesity. Out of 1784 participants across eight studies, 63 (3.5%) participants had class III obesity, compared to 9.2% of US adults with class III obesity. Six studies provided data on validity of energy intake assessment for class III obesity, with five of these showing underreporting. Participants with class III obesity are underrepresented in dietary validation studies. Future research should explore the role of weight status on dietary reporting accuracy.

Social desirability bias is related to children's energy intake in a laboratory test meal paradigm

Dietary intake is notoriously difficult to measure in children. Laboratory test meals address some of the methodological concerns of self-report methods, but may also be susceptible to social desirability bias, referring to the tendency for individuals to adjust their behaviors in order to be perceived more positively. The aim of the current study was to evaluate whether social desirability bias was associated with children's energy intake during a laboratory test meal, and whether this association varied by food type (total caloric intake, snack food intake, fruit/vegetable intake) and sex. A total of 82 children (M age = 9.45 ± 0.85; 50 % girls; 84.1 % rural; 85.4 % White) completed several surveys, including the Children's Social Desirability Scale and had their body composition measured. At lunchtime, they were granted access to a multi-array test meal (>5000 kcal). After adjusting for lean mass, fat mass, depressive symptoms, and parental food restriction, children who reported higher social desirability bias consumed fewer calories from snack foods (B = -11.58, p = .009, semi-partial correlation = -0.28). Boys with higher social desirability bias consumed less calories from fruits and vegetables (B = -6.47, p = .010, semi-partial correlation = -0.411); this association was not significant in girls. The desire to be perceived in a positive manner may influence children's eating behaviors in experimental paradigms. Replication studies with larger, more diverse pediatric samples are needed, as are strategies to reduce the effects of social desirability bias on test meal intake in order to enhance the validity of this dietary assessment approach.

The Impact of Weight Bias and Stigma on the 24 h Dietary Recall Process in Adults with Overweight and Obesity: A Pilot Study

People with overweight and obesity tend to both underreport dietary energy intake and experience weight stigma. This exploratory pilot study aimed to determine the relationship between weight bias and weight stigma and energy intake reporting accuracy. Thirty-nine weight-stable adults with BMI ≥ 25 completed three 24 h dietary recalls; indirect calorimetry to measure resting metabolic rate; a survey measuring weight stigma, psychosocial constructs, and physical activity; and a semi-structured qualitative interview. Multiple linear regression was used to determine if weight bias internalization, weight bias toward others, and experiences of weight stigma were predictive of the accuracy of energy reporting. A thematic analysis was conducted for the qualitative interviews. Weight stigma was reported by 64.1% of the sample. Weight stigma constructs did not predict the accuracy of energy intake reporting. People with obesity underreported by a mean of 477 kcals (p = 0.02). People classified as overweight overreported by a mean of 144 kcals, but this was not significant (p = 0.18). Participants reported a desire to report accurate data despite concerns about reporting socially undesirable foods. Future research should quantify the impact of weight stigma on energy reporting in 24 h recalls using a larger, more diverse sample size and objective measures like doubly labeled water for validation.

Nutrition Literacy Is Not Sufficient to Induce Needed Dietary Changes in Nonalcoholic Fatty Liver Disease

INTRODUCTION

Dietary and lifestyle changes are the first line of therapy for nonalcoholic fatty liver disease (NAFLD), the most prevalent liver disease in the western world. Nutrition literacy is the ability to understand nutrition information and implement that knowledge. We aimed to compare indicators of nutrition literacy in subjects with and without NAFLD in a representative US cohort.

METHODS

In a cross-sectional study using data from the National Health and Nutrition Examination Survey 2017-2018 cycle, we included 2,938 adult subjects with complete dietary and vibration-controlled transient elastography data and no alternative reason for hepatic steatosis. Nutrition literacy was assessed using questionnaires. Diet perception accuracy was assessed by comparing self-reported diet quality with objective diet quality scores-the Healthy Eating Index and alternative Mediterranean diet score-to assess real-world application of nutrition knowledge.

RESULTS

Nutrition literacy was not different between subjects with or without NAFLD ( P = 0.17): more than 90% of subjects reported using nutrition labels, and most of them correctly identified the meaning of daily value. Subjects with NAFLD had a lower-quality diet (Healthy Eating Index, P = 0.018; alternative Mediterranean diet, P = 0.013) and rated their diet as poorer ( P < 0.001). On self-assessment, only 27.8% of subjects overestimated their diet quality, while 37.5% consumed more calories than their self-assessed needs. Both accuracy measures were similar between subjects with NAFLD and those without ( P = 0.71 and 0.63, respectively). Subjects with NAFLD were more likely to report being advised to lose weight (42.1% vs 16.5%, P < 0.001) or to attempt losing weight (71.9% vs 60.9%, P < 0.001). Diet quality was not better in subjects with NAFLD who received dietary recommendations.

DISCUSSION

Subjects with NAFLD have poor diet quality despite receiving medical recommendations to lose weight and having nutrition literacy and perception that are comparable with subjects without NAFLD. Educational approaches may not be sufficient to promote weight loss and improve diet quality in NAFLD.

Is the energy balance explanation of the obesity epidemic wrong?

There is a striking discrepancy in both U.S and the U.K data between obesity rates, which are increasing, and self-reported food consumption rates, which are decreasing. There are two possible explanations for this discrepancy, namely that the widely accepted energy balance interpretation of obesity is wrong or that food consumption data are somehow biased. In a comment entitled "Obesity-an unexplained epidemic", Mozzafarian (2022) challenged the Energy Balance Model (EBM) and argued for a need to replace it with a novel biological theory. This challenge is premature, because there are psychological explanations for this discrepancy, namely that individuals with overweight and obesity underreport their food consumption and that this tendency has increased in recent years. To support these hypotheses, U.S and U.K data are reviewed that used the Doubly Labeled Water method (DLW), which is the gold standard for estimating energy expenditure. Such studies find not only consistent evidence of underreporting, but also that the discrepancy between measured energy expenditure and reported calorie consumption increased over time. Two psychological explanations for this pattern are discussed.