Similar to the glycemic index, which is an estimate of the rise in blood glucose after eating a particular food, the insulin index is an estimate of the rise in insulin after eating a particular food. In general, these indices are obvious: processed carbs have high glycemic and insulin indices, whereas whole foods are lower. Some exceptions are things like dairy and lean meat, which induce more insulin than you’d expect given to their low carbohydrate content…
When some protein-rich foods were discovered to induce insulin secretion, people thought this information might help type 1 diabetics more accurately calculate their insulin dose. Interesting rationale, worth testing.
Tl;dr: it didn’t work very well.
More of the protein-derived amino acids may have been incorporated into lean tissue, but the extra insulin load ended up causing hypoglycemia more often than not. Hypoglycemia is acutely more harmful than hyperglycemia, and is still quite harmful in the long-term. Some studies on incorporating the insulin index for type 1 diabetics are mixed, ie, increased or no change in risk of hypoglycemia, but no studies show it reduces the risk.
Eg, by increasing insulin dose to accommodate dietary protein, risk of hypoglycemia increased from 33% to 48% in this study.
And from 9.5% to 35.7% here.
Some type 1’s still do this, and that’s fine. Ymmv.
Drink a little too much of the Taubes Kool-Aid and you might figure that if processed carbs were bad because of insulin, and some protein-rich foods also induce insulin, then said protein-rich foods should also be avoided.
I’ve said there are some holes in Taubes’ theory, and while he never said to avoid protein-rich foods, this may be another one of those holes. Because just about every single diet study comparing higher to lower protein diets show a benefit of the former. I also don’t put too much stock in the Rosedale-mTOR theory for the same reason. Maybe some amino acids activate mTOR, and mTOR over-activation is associated with aging in some animal models, but none of this is reflected in the human studies. Maybe it’s because protein-rich foods are very nutrient-dense and activate other pathways which nullify any negative effects of insulin/mTOR, or maybe the theory is just flawed. Or both.
But condemning red meat and dairy because insulin is simply flawed. You may have other reasons for avoiding those foods, and that’s fine. It might help some type 1 diabetics more finely tune their insulin dose; that’s fine, too (as long as it doesn’t induce hypoglycemia).
Hypocaloric high protein spares lean mass relative to high carb (Piatti et al., 1994)
Protein: 15% -> 30%: increased leptin sensitivity, reduced appetite, and weight loss (Weigle et al., 2005).
If you’re one who benefits from [insulin-suppressive] low carb diets, then keep in mind that there may be more reasons than the insulin-suppressive nature of the diet; protein does not need to be restricted for this purpose (insulin levels actually even decline on higher protein diets in many studies).