HealthDay News — According to a study published in PLOS ONE, eating low-carbohydrate meals may lead to healthy changes in a woman’s metabolism that does not occur when consuming higher-carbohydrate meals; and the timing of exercise may play a role in how beneficial it is for metabolism.
This study included 32 healthy postmenopausal women, ages 50 to 65. The women were placed into 1 of 4 groups — high- or low-carb diet, and with or without exercise before meals.
The women had a meal at the lab the night before the study, and 2 study meals the next day — 1 in the morning and the other at 5 pm.
Each meal contained about 800 calories. The low-carb meal was 30% carbohydrate, 25% protein and 45% fat. The higher-carb meal was 60% carbohydrate, 15% protein and 25% fat. The exercise groups were moderately active for 2 hours and the exercise session ended 1 hour before a meal.
The researchers found that when the participants ate 3 meals containing 30% carbohydrates over a 24-hour period, they had a 30% reduction in their after-meal insulin resistance and insulin levels. With 3 meals containing 60% carbohydrates over 24 hours, there was no such reduction in insulin resistance or insulin levels. Exercising before eating raised women’s evening blood glucose levels, the researchers said.
“The principal significant finding of this study was the observation of parallel declines in evening postprandial insulin and glucagon-like peptide 1 responses. There was a concurrent decline in postprandial insulin resistance, as estimated by homeostatic model assessment of insulin resistance, after the third exposure to the low-carbohydrate meal in metabolically healthy individuals with normal glucose tolerance,” the authors write. “This outcome was unaffected by pre-meal exercise and absent after the high-carbohydrate meals.”
Lin PJ and Borer KT. “Third Exposure To A Reduced Carbohydrate Meal Lowers Evening Postprandial Insulin And GIP Responses And HOMA-IR Estimate Of Insulin Resistance”. PLOS ONE. 2016. doi: 10.1371/journal.pone.0165378. [Epub ahead of print]