Lentils and most beans are low on the glycemic index and have a balance of protein in them. As a T1 diabetic for 10+ years, I personally find that glycemic index is the leading indicator for how large and sustained my insulin spikes are

GI Info from ADA: http://www.diabetes.org/food-and-fitness/food/what-can-i-eat... GI info: https://www.health.harvard.edu/diseases-and-conditions/glyce... Lentil Macros: https://www.myfitnesspal.com/food/calories/macro-organic-gre... Black Bean Macros: https://www.myfitnesspal.com/food/calories/publix-dried-blac...