Almond Consumption and Glycemia

There is considerable evidence supporting a causal role for truncal visceral fat depots in glucose dysregulation. Individuals with large visceral fat depots have impaired suppression of free fatty acid release in response to insulin, elevated triglycerides and low concentrations of high density lipoprotein cholesterol. The high free fatty acid concentration may induce insulin resistance in the muscle and liver. There is more recent evidence that truncal subcutaneous fat depots are also problematic, though this literature is mixed. In contrast, gluteo-femoral fat depots have not been implicated in insulin resistance and dysregulation of carbohydrate metabolism. Failure to account for differences in the contributions of these depots will add noise to measurements of dietary interventions to mitigate glucose dysregulation. Previous studies have reported evidence indicating acute and chronic consumption of almonds improves glycemia. Acute effects are important indicators of health benefit, but longer-term trials, ones permitting identification of the effects of a dietary intervention on HbA1c, are more telling and clinically relevant. To more definitively establish the association between almond consumption and improved carbohydrate metabolism, we propose a six-month trial that contrasts the effects of almond consumption at optimal times of the day versus consumption of low nutrient dense snack foods on indices of carbohydrate metabolism, food intake and appetite in adults characterized by three distinct fat depots.

Participants will consume either almonds, or no nuts every day for 6 months. At baseline, participants will be weighed and undergo a DEXA scan to determine body fat composition and will be assigned a group. Blood will also be collected fasted and at stipulated times in response to a meal tolerance test to measure insulin, glucose, C-peptide, HbA1c, lipid panel, gut peptides, and compliance to the diet. Participants will be given links to complete appetite ratings and record food intake. Participants will report to the lab every two weeks to be weighed, and get a resupply of almonds (if in the almond group). At the two-week mark on months 2 and 4, participants will be weighed, blood will be taken to assess compliance to the diet, and links will be given to complete appetite ratings and record food intake. At month 6, all measurements from baseline will be repeated.