Some people process carbohydrates efficiently; others spike dramatically from the same foods. Research by Zeevi showed individual responses varied more than food-to-food variation. Factors: genetics, insulin sensitivity, muscle mass, activity, gut microbiome, metabolic health, age. Tolerance can improve with fat loss, muscle gain, and exercise — or worsen with weight gain and inactivity.
This companion covers why variation exists, factors affecting tolerance, whether it can change, and practical implications. (3 min read)