Insulin/glycemic response to food not associated with weight loss/gain.

[Eddy Edson]

Yet more evidence that glycemic response and insulin resistance don't cause weight gain independently of excess calorie intake, for both "normal" people and people with metabolic syndrome. So yet more evidence against central components of popular low-carb dogma.

Effect of a Personalized Diet to Reduce Postprandial Glycemic Response in Adults With Obesity

This randomized clinical trial compares personalized vs standardized caloric-restricted weight loss interventions in terms of percentage of weight loss among adults with high postprandial glycemic responses and obesity.

jamanetwork.com

Importance Interindividual variability in postprandial glycemic response (PPGR) to the same foods may explain why low glycemic index or load and low-carbohydrate diet interventions have mixed weight loss outcomes. A precision nutrition approach that estimates personalized PPGR to specific foods may be more efficacious for weight loss.

Objective To compare a standardized low-fat vs a personalized diet regarding percentage of weight loss in adults with abnormal glucose metabolism and obesity.

Design, Setting, and Participants The Personal Diet Study was a single-center, population-based, 6-month randomized clinical trial with measurements at baseline (0 months) and 3 and 6 months conducted from February 12, 2018, to October 28, 2021. A total of 269 adults aged 18 to 80 years with a body mass index (calculated as weight in kilograms divided by height in meters squared) ranging from 27 to 50 and a hemoglobin A1c level ranging from 5.7% to 8.0% were recruited. Individuals were excluded if receiving medications other than metformin or with evidence of kidney disease, assessed as an estimated glomerular filtration rate of less than 60 mL/min/1.73 m2 using the Chronic Kidney Disease Epidemiology Collaboration equation, to avoid recruiting patients with advanced type 2 diabetes.

Interventions Participants were randomized to either a low-fat diet (<25% of energy intake; standardized group) or a personalized diet that estimates PPGR to foods using a machine learning algorithm (personalized group). Participants in both groups received a total of 14 behavioral counseling sessions and self-monitored dietary intake. In addition, the participants in the personalized group received color-coded meal scores on estimated PPGR delivered via a mobile app.

Main Outcomes and Measures The primary outcome was the percentage of weight loss from baseline to 6 months. Secondary outcomes included changes in body composition (fat mass, fat-free mass, and percentage of body weight), resting energy expenditure, and adaptive thermogenesis. Data were collected at baseline and 3 and 6 months. Analysis was based on intention to treat using linear mixed modeling.

Results Of a total of 204 adults randomized, 199 (102 in the personalized group vs 97 in the standardized group) contributed data (mean [SD] age, 58 [11] years; 133 women [66.8%]; mean [SD] body mass index, 33.9 [4.8]). Weight change at 6 months was −4.31% (95% CI, −5.37% to −3.24%) for the standardized group and −3.26% (95% CI, −4.25% to −2.26%) for the personalized group, which was not significantly different (difference between groups, 1.05% [95% CI, −0.40% to 2.50%]; P = .16). There were no between-group differences in body composition and adaptive thermogenesis; however, the change in resting energy expenditure was significantly greater in the standardized group from 0 to 6 months (difference between groups, 92.3 [95% CI, 0.9-183.8] kcal/d; P = .05).

Conclusions and Relevance A personalized diet targeting a reduction in PPGR did not result in greater weight loss compared with a low-fat diet at 6 months. Future studies should assess methods of increasing dietary self-monitoring adherence and intervention exposure.

 

[everydayupsanddowns]

There’s not a ‘one size fits all’ approach to diabetes management for sure.

Did the study record differences in any changes to HbA1c between the groups? Edit: Doesn't look like they included that as an outcome measure because of the mixed D and non-D cohort. They also seemed to avoid recruiting anyone whose BG was really struggling (eg with what they called ‘advanced diabetes’).

Shame they didn’t have funding to keep recording for longer than 6 months. Would have been interesting to see what happened at 12 and 24 with the variation of weight loss in both groups over the 6 month period.

 

[Eddy Edson]

There’s not a ‘one size fits all’ approach to diabetes management for sure.

Did the study record differences in any changes to HbA1c between the groups? Edit: Doesn't look like they included that as an outcome measure because of the mixed D and non-D cohort. They also seemed to avoid recruiting anyone whose BG was really struggling (eg with what they called ‘advanced diabetes’).

Shame they didn’t have funding to keep recording for longer than 6 months. Would have been interesting to see what happened at 12 and 24 with the variation of weight loss in both groups over the 6 month period.

More interesting than HbA1c is whether the precision approach actually succeeded in reducing post-prandial glycemia. If it didn't then I suppose the paper is a bit meaningless. On a twitter thread

https://twitter.com/x/status/1575191955364986880

one of the authors said this is addressed in an upcoming paper - kind of weird ...

Also note the comments on adherence problems, given which overall probably wouldn't call the evidence in this paper very strong by itself. But it fits within a large body of high-quality evidence with the samke kind of implications.

 

[42istheanswer]

More interesting than HbA1c is whether the precision approach actually succeeded in reducing post-prandial glycemia. If it didn't then I suppose the paper is a bit meaningless. On a twitter thread one of the authors said this is addressed in an upcoming paper - kind of weird ...

Not at all weird, perfectly normal in academia. Most university lecturers nowadays have it written until their contracts that they must have their name on a minimum number of research papers published in peer- reviewed journals every year. The programme leader when I did my Return to Practice course told us that at that university it was a minimum of 4. Doing 4 different research projects each year plus teaching is a little difficult, thus they do bits for each other's papers (e.g. the stats calculations) to be added as a secondary researcher on the list of authors, and try to get multiple papers out of the one research project.

 

[Eddy Edson]

Not at all weird, perfectly normal in academia. Most university lecturers nowadays have it written until their contracts that they must have their name on a minimum number of research papers published in peer- reviewed journals every year. The programme leader when I did my Return to Practice course told us that at that university it was a minimum of 4. Doing 4 different research projects each year plus teaching is a little difficult, thus they do bits for each other's papers (e.g. the stats calculations) to be added as a secondary researcher on the list of authors, and try to get multiple papers out of the one research project.

Response from author:

https://twitter.com/x/status/1576881241382850562

FWIW.

From the SI, the precision group carb intake reduced by about 50g per day on average from about 210g per day at baseline (with wide variance in each).

By itself I would guess that wouldn't have had much impact on glycemic response, given all the evidence that on average changes in carb intake don't have much impact for "normal" people or people with moderately well controlled T2D, until you get down to real keto levels.

However, I think you'd expect the impact on insulin response to be fairly large, and from what I understand of the common low-carb dogma, that would be the thing which is supposed to cause weight gain. There's actually a large amount of evidence that this dogma is in fact not correct, but I'd have thought it was a better focus for this experiment. More difficult to measure, though, and I'm probably missing something.

Anyway, I guess it will be interesting to see in the upcoming papers whether the results of the precision approach were different to those averaged expectations.