Effect of two diets with varying insulin demand on day-long profiles of blood glucose and insulin in lean, young healthy adults

In this within-subject crossover study, healthy subjects will consume two different diets with varying food insulin index (FII) on two separate occasions. The washout period in between the low FII and high FII diets will be at least 7 days. Each test diet will comprise breakfast, morning snack and lunch, which will be carefully designed to be healthy western diet reflecting adherence to the average adult energy requirement in Australia (energy percentage for carbohydrate 50%, protein 20%, fat 30%). The high FII diet will comprise white bread, yogurt and eggs for breakfast, cookie and Mars bar for morning snack and whole-meal bread, cheese and baked beans for lunch. The low FII diet will comprise grain bread, milk and All-bran cereal for breakfast, walnuts and raisins for morning snack, corn, roast chicken and tortillas for lunch. Both diets will be matched for macronutrient composition, glycemic index and fiber content, but two-fold difference in FII values. On each occasion, breakfast, snack meal and lunch will be consumed by subjects at 0800, 1100 and 1300 during the 8-hour test session. Finger-prick blood samples will be collected before meal (0 min) and every 30 mins after starting eating the meals and assayed for glucose and insulin.