Studies now suggest that imbalance within the gut microbiome can lead to increased levels of insulin resistance. Gut microbes may influence insulin levels and also impact leptin signaling. As a result, they can influence cravings and food intake. Sweet potatoes and yams With a glycemic index of just 44, these types of potatoes are loaded with nutrients – from vitamin C, to vitamin A, to potassium, and they contain a high amount of fiber. Natural, unsalted roasted or raw nuts are perfect snacks. Just make sure to avoid sugary coatings. Nuts are loaded with fiber while having a glycemic index score of 55 or less, depending on the nut.