One problem with the aforementioned theory is that insulin secretion is also stimulated by amino acids. In fact, studies have shown insulin response to equivalent loads carbohydrate and protein loads is similar. The only difference in response to the carbohydrate vs protein load was that the insulin peaked earlier with the carbohydrate than protein load; the total amount of insulin produced in response to the loads was the same. The greatest amount of insulin is produced, in fact, from a meal consisting of a combination of protein and carbohydrate (ref from Meg).

Ludwig DS, Majzoub JA,. Al-Zahrani A, Dallal GE, Blanco I, Roberts S. (1999)High Glycemic Index Foods, Overeating, and Obesity Publication: Pediatrics;103:March

See http://commentator.tufts.edu/archive/wt_
mgt/glycemic.html

The glycemic index (GI) is a measure that quantifies the rise in blood glucose that occurs after eating a carbohydrate-containing meal. Most starchy foods commonly eaten in North America, chiefly refined grain products and potatoes, have a high GI, exceeding even that of table sugar. By contrast, vegetables, legumes, and fruits generally have a low GI. Using a crossover study design, metabolic changes and voluntary food intake were observed among 12 obese adolescent boys in the hours following ingestion of one of three standard test breakfasts that varied in dietary GI. The high-GI meal was associated with higher serum insulin levels, higher plasma epinephrine, lower plasma glucagon levels, lower post-absorptive plasma glucose and lower serum fatty acid levels, compared to the low-GI meal. Voluntary energy intake and self-reported hunger were substantially greater after the high-GI meal compared with either the medium- or low-GI meal.