“Effects of a low carbohydrate diet on energy expenditure during weight loss maintenance: randomized trial” From The British Medical Journal – With Links To Additional Resources

Posted on November 14, 2018 by Tom Wade MD

In addition to the article cited in the title, here are links to other posts related to weight loss and the low carbohydrate ketogenic diet:

The following is the abstract from Resource (1) below, Effects of a low carbohydrate diet on energy expenditure during weight loss maintenance: randomized trial, from The British Medical Journal:

ABSTRACT

OBJECTIVE
To determine the effects of diets varying in carbohydrate to fat ratio on total energy expenditure.

DESIGN
Randomized trial.

SETTING
Multicenter collaboration at US two sites, August 2014 to May 2017.

PARTICIPANTS
164 adults aged 18-65 years with a body mass index of 25 or more.

INTERVENTIONS
After 12% (within 2%) weight loss on a run-in diet, participants were randomly assigned to one of three test diets according to carbohydrate content (high, 60%, n=54; moderate, 40%, n=53; or low, 20%, n=57) for 20 weeks. Test diets were controlled for protein and were energy adjusted to maintain weight loss within 2 kg. To test for effect modification predicted by the carbohydrate-insulin model, the sample was divided into thirds of pre-weight loss insulin secretion (insulin concentration 30 minutes after oral glucose).

MAIN OUTCOME MEASURES
The primary outcome was total energy expenditure,
measured with doubly labeled water, by intention-to-treat
analysis. Per protocol analysis included participants who maintained target weight loss, potentially providing a more precise effect estimate. Secondary outcomes were resting energy expenditure, measures of physical activity, and levels of the
metabolic hormones leptin and ghrelin.

RESULTS
Total energy expenditure differed by diet in the intention-to-treat analysis (n=162, P=0.002), with a linear trend of 52 kcal/d (95% confidence interval 23 to 82) for every 10% decrease in the contribution of carbohydrate to total energy intake (1 kcal=4.18
kJ=0.00418 MJ). Change in total energy expenditure was 91 kcal/d (95% confidence interval −29 to 210) greater in participants assigned to the moderate carbohydrate diet and 209 kcal/d (91 to 326) greater in those assigned to the low carbohydrate diet compared with the high carbohydrate diet. In the per protocol analysis (n=120, P<0.001), the respective
differences were 131 kcal/d (−6 to 267) and 278 kcal/d (144 to 411). Among participants in the highest third of pre-weight loss insulin secretion, the difference between the low and high carbohydrate diet was 308 kcal/d in the intention-to-treat analysis and 478 kcal/d in the per protocol analysis (P<0.004).
Ghrelin was significantly lower in participants assigned to the low carbohydrate diet compared with those assigned to the high carbohydrate diet (both analyses). Leptin was also significantly lower in participants assigned to the low carbohydrate diet
(per protocol).

CONCLUSIONS
Consistent with the carbohydrate-insulin model,
lowering dietary carbohydrate increased energy
expenditure during weight loss maintenance. This
metabolic effect may improve the success of obesity
treatment, especially among those with high insulin
secretion.

Resources:

(1) Effects of a low carbohydrate diet on energy expenditure during
weight loss maintenance: randomized trial [Full Text HTML] [Full Text PDF]. BMJ 2018; 363 doi: https://doi.org/10.1136/bmj.k4583 (Published 14 November 2018)

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