Effect of diet composition on energy expenditure during weight loss: the POUNDS LOST Study

Abstract

Background Weight loss reduces energy expenditure, but the contribution of different macronutrients to this change is unclear. Hypothesis We tested the hypothesis that macronutrient composition of the diet might affect the partitioning of energy expenditure during weight loss. Design A sub-study of 99 participants from the POUNDS LOST trial had total energy expenditure (TEE) measured by doubly labeled water and resting energy expenditure (REE) measured by indirect calorimetry at baseline and repeated at 6 months in 89 participants. Participants were randomly assigned to one of 4 diets with either 15% or 25% protein and 20% or 40% fat. Results TEE and REE were positively correlated with each other and with fat free mass and body fat, at baseline and 6 months. The average weight loss of 8.1±0.65 kg (LSmean±SE) reduced TEE by 120±56 kcal/d and REE by 136±18 kcal/d. A greater weight loss at 6 months was associated with a greater decrease in TEE and REE. Participants eating the high fat diet lost significantly more fat free mass (1.52±0.55 kg) than the low fat diet group (p<0.05). Participants eating the low fat diet had significantly higher measures of physical activity than the high fat group. Conclusion A greater weight loss was associated with a larger decrease in both TEE and REE. The low fat diet was associated with significant changes in fat free body mass and energy expenditure from physical activity compared to the high fat diet.

Central and peripheral control of food intake

“…Cholecystokinin (CCK) was the fi rst gut hormone shown to modulate the food intake (Bray and York 1972). CCK is secreted postprandial from I cells of the small intestine into the circulation with a plasma half-life of a few minutes.…”

“…However, opposite responses are triggered when body weight increases. Body weight can change only when energy intake is not equal to energy expenditure over a given period of time (Bray et al 2012). A complex physiological control system is involved in the maintenance of the energy balance.…”

Maintaining Weight Loss by Decreasing Sedentary Time: A Patient and Physician’s Perspective

“…Unfortunately, within 1 year individuals on average regain 50% of what was lost [1]. In fact, current science suggests that ''eat less, move more'' does not in fact lead to sustained weight loss [2,3] because the body will sense the lower weight as abnormally low and respond by increasing appetite signals [4] and decreasing the resting metabolic rate [5]. These adaptations oppose sustained weight loss.…”

Higher-protein diets for health?

“…Owing to lack of information concerning the effect of diets on direct patient outcomes, more available and usually reported surrogate outcomes such as anthropometry and blood biomarkers were used for their analyses. Their results indicate that diets higher in protein have beneficial effects on BMI, waist circumference, systolic and diastolic blood pressure, high-density lipoproteins (HDL), fasting insulin and triglycerides; however, the effects were small to moderate and when analyzed for lower risk of bias the effects on some parameters such as HDL, fasting insulin and triglycerides were annulled.For those who consider that the macronutrient composition of the diet may potentially have a role in curbing energy intake, influencing energy metabolism and providing health benefits, the results of the meta-analysis by Santesso et al3 are moderately satisfying and supportive, but may unfortunately be rendered less convincing by reports from the POUNDS LOST trial, 4-6 which purportedly studied differences between high-and low-protein, high-and low-fat and high-and lowcarbohydrate diets.As far as the protein diets are concerned, the experimental differences in protein energy intake were not sufficient, B3% rather than the intended 10%, to expect any differences to be observed and although the authors allude to this in the abstract and discussion in one of their articles, 6 it is not evident from the titles and abstracts of their other publications, 4,6 which if taken at face value are incorrect and misleading. In their defense they suggest that larger contrasts in protein intake may be required for selective changes in body composition, but that such diets would fall outside the Institute of Medicine's Acceptable Macronutrient Distribution Range.…”

“…As far as the protein diets are concerned, the experimental differences in protein energy intake were not sufficient, B3% rather than the intended 10%, to expect any differences to be observed and although the authors allude to this in the abstract and discussion in one of their articles, 6 it is not evident from the titles and abstracts of their other publications, 4,6 which if taken at face value are incorrect and misleading. In their defense they suggest that larger contrasts in protein intake may be required for selective changes in body composition, but that such diets would fall outside the Institute of Medicine's Acceptable Macronutrient Distribution Range.…”