Most gym goers don’t understand how important insulin is to building muscle and getting lean.  In this post, I’ll break down what you need to know and how to apply it.

What you may already know about insulin

Insulin is the main hormone that regulates your blood sugar level.  After you eat, your body releases insulin to shuttle sugar out of the blood and into the cells of your muscles and organs.  If your body doesn’t produce enough insulin or doesn’t use it properly, then you have a serious medical condition called diabetes.

What you might not know about insulin

Insulin is a powerful anabolic agent.  It will make you gain weight by increasing your appetite and turning off your body’s fat burning mechanism.  That’s why weight gain is listed as one of the side effects of taking insulin shots.  Eating refined sugar or other high glycemic foods throughout the day will have a similar effect by triggering your body to release large amounts of insulin.  Common high glycemic foods are white bread, white potatoes, white rice, and any food high in refined sugar.  For a more complete list, try a Google search.

Insulin causes your body to store fat by funneling blood glucose to your fat cells.  However, it also has the ability to build muscle by sending blood glucose and other nutrients into the muscle cells.  This is where it pays to understand when insulin favors fat storage and when it favors muscle growth.  When insulin is released following a meal, if your liver and muscle glycogen (stored carbohydrates) are low, insulin will first shuttle blood sugar to your liver and muscles.  Once your liver and muscle glycogen levels are full, insulin will cause the additional blood sugar to be stored as fat.  Think of your muscles as a gas tank where carbohydrates are the fuel.  If your tank is empty and you eat carbs, insulin will fill the tank with carbs.  Once the tank is full, the excess carbs will be stored as fat.

Another key factor is how sensitive the cells of your muscles and organs are to insulin.  Right after a workout, your muscle cells are particularly sensitive to insulin and will soak up the blood sugar and other available nutrients which aid in recovery and muscle growth.  On the flip side, your cells may become less sensitive to insulin (i.e. insulin resistant) if you consistently eat a lot of sugar or high glycemic foods over a long period of time.

How to apply what we know about insulin

If your main goal is to lose bodyweight and body fat, you should aim to keep your insulin levels low.  Remember insulin causes weight gain.  Cut all refined sugar and other high glycemic foods from your diet.  The simplest way to do this is through a very low carbohydrate diet, but it can also be achieved through a moderate carbohydrate diet if you’re careful to choose only low glycemic foods.  Of course, your total caloric intake is also critical to weight loss, but keeping your insulin level low will make a huge difference by lowering your food cravings and setting the metabolic wheels in motion to burn fat.

If your main goal is to bulk up, then you should keep your insulin levels high by eating carbohydrates throughout the day, in addition to quality protein and healthy fats.  You will gain some body fat, but you will also gain muscle by taking advantage of the anabolic properties of insulin.  On such a bulking diet, consuming moderate amounts of refined sugar and other high glycemic foods will help by raising insulin levels, but don’t overdo it on the simple carbs or you’ll gain an unhealthy amount of fat and risk becoming insulin resistant.

Lastly, if your goal is to gain muscle and lose fat, eat some carbs with breakfast and after your workout, but eat low carbs the rest of the day.  After a night’s sleep, your body’s glycogen levels are partially depleted, so consuming 30-50 grams of carbs with breakfast will raise your insulin levels and send blood sugar into the muscles for repair and growth.  After a workout, your muscles will be both depleted of glycogen and hyper sensitive to insulin, so it’s the perfect time to consume simple carbs to raise insulin levels and funnel nutrients into the muscles.  30-80 grams of simple carbs along with 30-60 grams of high quality protein within an hour of finishing your workout is recommended.  The rest of the day, stick with low carbs which will keep you in fat burning mode and help retain your insulin sensitivity.

In summary, be careful about how many carbs you eat, the type of carbs you eat and when you eat them.  Insulin has the power to build muscle or fat, so it pays to use it to your advantage.