Particularly in those with elevated levels to begin with. Glycemic variability may be reduced,, and average glucose levels throughout the day will tend to be lower. Ketogenic diets tend to worsen carbohydrate tolerance during postprandial testing. But all those studies were very small, and not all research on the keto diet is as promising. One American Society for Clinical Nutrition May 2006 study of 20 participants found that those on the diet didn’t lose more weight than those on a non-keto diet.