In healthy premenopausal black and white women with overweight and obesity, consumption of a short-term, eucaloric, high-fat diet does not appear to yield a decrease in peripheral insulin sensitivity compared with a low-fat diet, according to recent findings.
Jeanine B. Albu, MD, of St. Luke’s Roosevelt Hospital Center and Icahn School of Medicine at Mount Sinai in New York, and colleagues evaluated 23 healthy black and white women aged 25 to 45 years with overweight or obesity (BMI, 25-40 kg/m2) recruited from St. Luke’s Roosevelt Hospital Center. For 7 consecutive days, participants consumed one of two diets: a low-fat (30% fat, 50% carbohydrate and 20% protein) or a high-fat (50% fat, 30% carbohydrate and 20% protein) diet. On day 8, insulin sensitivity and substrate utilization were evaluated before and during a euglycemic hyperinsulinemic clamp. A washout period of at least 2 weeks was implemented between dietary regimens, and all measurements were taken during the follicular phase of the menstrual cycle.
Peripheral insulin sensitivity and metabolic flexibility during the euglycemic hyperinsulinemic clamp were the main outcome measures.
Insulin sensitivity, calculated as glucose disposal rate per kilogram of fat-free mass and divided by the steady-state insulin level, was not significantly reduced after the high-fat vs. the low-fat diet (0.09 vs. 0.08; P = .09). There was no significant interaction of diet by race (P = .6).
Metabolic flexibility, estimated as change in nonprotein respiratory quotient during the hyperinsulinemic clamp, was not changed by the diets (P = .48 for high fat vs. low fat); no significant diet by race interaction was found (P = .9).
Black participants had a lower insulin clearance rate compared with white participants (P < .05).
“Peripheral insulin sensitivity was not deleteriously affected by 1 week of a eucaloric [high-fat] diet (50% of total Kcal from fat), compared to a [low-fat] (30% of total Kcal from fat), diet, in healthy, premenopausal, overweight and obesity African American and non-Hispanic white women,” the researchers wrote. “Our findings need to be verified with regard to the effect on hepatic insulin response and more importantly in other susceptible populations.” – by Jennifer Byrne
Albu reports being an associate editor of BMJ Open Diabetes Research & Care and receiving grant funding from Eli Lilly, Merck, Novo Nordisk, Roche, Takeda and Weight Watchers. One of the researchers reports being an employee of GlaxoSmithKline.