We know the hormone Insulin and fat loss don’t mix and we also know that too much carbohydrate/sugar in the diet and the resultant chronically elevated insulin levels increase the chance of becoming insulin resistant and type 2 diabetic.
But how does insulin affect building muscle?
If you want to build muscle, insulin will help you. It’s your friend. Insulin is an anabolic hormone just like growth hormone (GH) and testosterone. Insulin helps drive nutrients such as glucose and amino acids, which are extremely important for muscle building, into your muscle tissue. This is especially important for ‘hard gainers’. 
Carbs/sugars are the foods that are primarily responsible for causing a major spike in insulin. Protein can cause an insulin spike, but not to the same extent of carbs/sugars. Insulin’s help in building muscle doesn’t mean we should eat heaps of cake and bread all day to keep releasing insulin. Consistent insulin secretion will lead to becoming insulin resistant and result in muscle tissue not responding well to it. We must time our insulin secretion, or at least limit it, so it doesn’t lose its effectiveness.
My preferred times to spike insulin are pre and post-workout. In some cases before bed and early in the morning can also be beneficial to you. Some people can get away with all four of these times, while some people may only need to eat carbs/sugars once per day (on training days) and still make good gains in building muscle. It really depends on the type of person you are.
If you’re a ‘hard gainer’ four spikes per day might be necessary. For people who look at cake and gain weight, pre or post-workout, with an evening carb meal should be enough. Some people who gain fat very easy from carbs can just get away with 1 or two carb meals a week and instead take on extra protein especially around their workouts.
Post-workout, your muscles will be primed for nutrients as you’ve just performed resistance training and the muscles are screaming out for nutrients such as amino acids and glucose which are needed for repair work and building new muscle. Spiking insulin pre and post-workout will help drive nutrients to the muscles.
Insulin in the morning is a good way of suppressing cortisol a stress hormone which is catabolic. Personally I don’t like eating carbs and sugars in the morning as the sudden dip in blood sugar caused by insulin makes me feel tired and sluggish. It’s the same feeling you get after you eating a big dirty sandwich at lunch – tired and drowsy. That brings us to our next point, eating carbs and sugars before bed.
Having a meal before bed with sugar and carbs will relax you. While you’re asleep your body carries out most of its repairs including muscle building, hair growth, bone growth and much more. A surge of insulin before bed isn’t such a bad idea because it helps with building muscle and that’s something you’ll want to happen while you sleep. I would suggest eating carbs and sugars late on days you train, as opposed to non-training days, as your muscles will be more receptive to sugars and carbohydrates.
Carbohydrate choice!
So I’ve explained a little about insulin and its benefits in building muscle, but that doesn’t mean you can eat bread and pasta all day in the name of insulin production and muscle building.
Without going into too much detail, certain types of carbohydrates and sugars such as wheat and fructose cause higher amounts of Inflammation. Inflammation isn’t good as it prohibits your cells from functioning properly, not to mention (IMO) being the root cause of heart disease. It has a negative effect on muscle growth because it affects the cell’s uptake of glucose and amino acids. So the cell, being muscle, can’t take in the nutrients that it requires for growth.
Eating wheat-free carbohydrate foods such as white rice, sweet potato, potato, parsnips and pure glucose will not cause as much inflammation, and are far easier to digest and breakdown into glucose.
So now you know a little about insulin and why it’s pretty cool when building muscle.
Jay Farrant Personal Trainer Dublin