Low-Carb Diet Could Help Lower Insulin Resistance

A low-carbohydrate diet may help control glucose and insulin levels in middle-age women, according to new data.

For their study, researchers provided 32 postmenopausal metabolically healthy women with 3 meals: a pretrial isocaloric meal and 2 isocaloric meals during the trial day. The women either performed or did not perform 2 hours of moderate exercise before the last 2 meals. The meals contained either 30% or 60% carbohydrates.
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The researchers measured plasma glucose, insulin, glucagon, glucose-dependent insulinotropic peptide (GIP), glucagon-like peptide 1 (GLP-1), free fatty acids (FFAs), and D-3-hydroxybutyrate concentrations 4 hours after participants ate and 3 hours after participants exercised.

Insulin resistance was measured using the homeostasis-model assessment (HOMA-IR).

After analyzing the results, the researchers found that the third low-carbohydrate meal lowered evening insulin by 39% without exercise and by 31% with exercise, lowered GIP by 48% without exercise and by 45% with exercise, and lowered evening insulin resistance by 37% without exercise and by 24% with exercise.

On the contrary, women who ate high-carbohydrate meals sustained high postprandial insulin levels.

Exercising before eating a low-carbohydrate meal did not affect insulin, GIP, or HOMA-IR levels, but it exacerbated evening hyperglycemia.

“Evening postprandial insulin and GIP responses and insulin resistance declined by over 30% after 3 meals that limited daily carbohydrate intake to 30% compared to no such changes after three 60%-carbohydrate meals, an effect that was independent of pre-meal exercise,” the researchers concluded.

“The parallel timing and magnitude of postprandial insulin and GIP changes suggest their dependence on a delayed intestinal adaptation to a low-carbohydrate diet. Pre-meal exercise exacerbated glucose intolerance with both diets most likely due to impairment of insulin signaling by pre-meal elevation of FFAs.”

—Amanda Balbi

Reference:

Lin P-J, Borer KT. Third exposure to a reduced carbohydrate meal lowers evening postprandial insulin and GIP responses and HOMA-IR estimate of insulin resistance [published online October 31, 2016]. PLoS One. http://dx.doi.org/10.1371/journal.pone.0165378.