Combining the understanding of resistance training with a knowledge of how food impacts insulin allows adjustment of exercise and food timing. Manipulating these can allow tailored results for muscle gain and/or fat loss.
Insulin can be used to build muscle and therefore provides one of the most valuable tools to increase metabolic efficiency. But if it is not controlled it will dramatically increase fat storage. The key to using it to your advantage lies in the art of meal and exercise timing.
Obese individuals already have poor insulin sensitivity and very high resting insulin levels. Therefore they should minimize any type of glucose (sugar or starch) both pre- and post-workout.
The common belief that carbs should be consumed after a workout does not apply as strongly to those seeking fat loss. Instead, these types should time their carbohydrate intake at the most insulin sensitive times.
The best times to consume any insulin promoting carbs for these types are in the morning after an overnight fast, and then within one hour after a workout. The carbohydrate load should be smaller and lower on the glycemic index.
Pre-workout carbohydrate intake is not wised because it will raise insulin, further shutting down fat loss during the workout and give the body sugar to burn instead of fat. Protein should be used for the pre-workout meal instead.
For those wanting to optimize muscle growth, carbohydrates should be eaten throughout the day. Small amounts can be taken 45 to 60 minutes before a workout, and larger amounts should be taken after the workout. Good post-workout choices are high glycemic index carbs like bananas, potatoes and pasta.
For those wanting both muscle gain and fat loss a combination of the two strategies above is wise. Limiting high starch meals to morning and post-workout, but increasing the amounts and glycemic index of carbs in the post-workout period will help build muscle without providing too much of a stimulus for fat storage.
One final caveat when managing insulin is dairy. Dairy foods are low on the glycemic index but are unique as a protein source because they stimulate insulin much more than their glycemic index would suggest. They are what is called an insulinogenic (insulin generating) protein.
This is a good thing for those seeking muscle gain and can even provide some benefit for fat loss. Whey protein and other dairy proteins can be used to provide an insulin stimulus without the high sugar load.
However, the recommendation to use dairy combined with a high sugar load (i.e., chocolate milk) may aid muscle gain but will surely put the brakes on fat loss. This approach would be better suited to those strictly seeking muscle gains over fat loss goals.