Personalised diet for reducing postprandial glycemia no better than low-fat diet for weight loss: JAMA

NEW YORK: According to the Personal Diet Study, which was published in JAMA Network Open, adopting a personalized diet aimed at lowering postprandial glycemic response (PPGR) wasn't any more effective for weight loss than a standard low-fat diet.

The ideal diet for weight loss is a topic of intense discussion. Interindividual variability in postprandial glycemic response (PPGR) to the same types of food may reveal why low glycemic index or load and low-carbohydrate diet approaches have mixed weight loss outcomes. It may be more effective to lose weight using a precision nutrition method that calculates tailored PPGR to particular foods.

The goal of the study was to assess the percentage of weight loss in individuals with impaired glucose metabolism and obesity between a regular low-fat diet and a personalized diet.

From February 12, 2018, to October 28, 2021, the Personal Diet Study was a single-center, population-based, 6-month randomized clinical experiment with assessments at baseline (0 months), 3 months, and 6 months.

A total of 269 adults between the ages of 18 and 80 were enrolled in the study, and their body mass index ranged from 27 to 50 and their hemoglobin A1c level from 5.7% to 8.0%. People who were taking drugs other than metformin or who had renal disease, as determined by an estimated glomerular filtration rate of less than 60 mL/min/1.73 m2, were excluded from the study. Participants were randomly assigned to either a low-fat diet (25% of energy intake; standardized group) or a customized diet that uses a machine learning system to assess PPGR to meals (personalized group).

The percentage of weight decrease from the baseline to six months was the main result. Changes in resting energy expenditure, adaptive thermogenesis, and body composition (fat mass, fat-free mass, and % of body weight) were secondary outcomes. Data was gathered at baseline, three, and six months. Analysis was done using linear mixed modeling with the objective of treating. 199 out of the 204 persons who were randomly assigned provided data (102 in the personalized group vs. 97 in the standardized group.

Conclusive points of the study:

• After six months, those randomly assigned to a standardized low-fat diet dropped 4.31% of body weight, while those in the personalized diet group lost 3.26% (a between-group difference of 1.05%).
• This resulted in an average weight loss of 4.16 kg (9.17 lb) for those following a low-fat diet and 3.14 kg (6.9 lb) for those following a customized diet, both of which fell short of the trial's main objective.
• Adaptive thermogenesis and body composition changes also did not significantly differ between groups, with the numbers favoring the control group.
• When compared to the group following a personalized diet, low-fat dieters experienced a higher change in resting energy expenditure.

"Future research is required to create and test a weight loss-specific algorithm that takes into account features from the energy balance model as well as key aspects of body weight regulation, such as appetitive hormones (such as leptin and glucagon-like peptide 1), total energy expenditure, and fat mass", the team asserted.

The authors came to the conclusion that, amidst the randomized clinical trial's unique design, there were no appreciable differences in the percentage of weight reduction between a conventional low-fat diet and a precision nutrition diet intended to lower PPGR.

REFERENCE

Popp CJ, et al "Effect of a personalized diet to reduce postprandial glycemic response vs a low-fat diet on weight loss in adults with abnormal glucose metabolism and obesity: a randomized clinical trial" JAMA Netw Open 2022; DOI:10.1001/jamanetworkopen.2022.33760