Insulin and the Importance of Meal Timing

This week, I have an awesome guest post from friend and nutrition expert Sara Pindera. Sara is a friendly Canadian with a Bachelor of Science Degree, specialising in Nutrition and Nutraceuticals. She has additional experience in food and product marketing and has written numerous articles on fitness and nutrition on the Gymaholic site. You can follow her on YouTube and Instagram!




Food keeps us alive, it keeps our bodies functioning properly and fuels them for daily tasks, whatever those tasks may be. We are all individuals, different in our genetics, eating habits and activity levels, but some mechanisms function in roughly the same way for all of us.

These mechanisms have developed to protect the body and ensure our survival. Fortunately or unfortunately, most of us don’t have to fight so hard anymore, so these age old mechanisms can work against us in a sedentary lifestyle. They can even work against you in an active lifestyle, acting as drag and limiting your progress. They can also work with you, but in order to use them to your advantage, you have to better understand how they work.

If you only think of food as fuel for your body, you need to change your way of thinking. What you eat and when you eat it can have a snowball effect, setting off various triggers in the body that can magnify different bodily functions in just minutes or hours.

The ‘state’ that your body is in can have massive effects on your goals. The two main states are the fed state and the fasted state, and we cycle through these different states multiple times a day by, you guessed it, feeding and fasting. But it’s more than just that, because putting yourself in the right state at the right time can give you an incredible boost in fat loss or building muscle.

The body states are mostly characterized by the presence of two main hormones: insulin (fed state) and glucagon (fasted state). The purpose of these states and these hormones is mainly to control the blood glucose (sugar) levels.

Insulin removes excess blood glucose by pulling it into the muscle and liver, but it also promotes the uptake of fats and proteins, and facilitates the storage of these macronutrients. It’s essentially an anabolic, or building hormone. It also inhibits the actions of glucagon.

Glucagon has the exact opposite function of insulin: it is a catabolic hormone that signals the liver to breakdown its stored glucose and release it into the blood. It also triggers the breakdown of fats and inhibits the actions of insulin. You can probably see why both hormones may help or hinder your progress, depending on what your goals are.

Normal people only experience mild symptoms when blood sugar is slightly out of normal range, and we can still function even after skipping meals or eating an entire box of cookies. Our bodies simply pump out more of these hormones. There are dangerous consequences if these hormones stop working, which is why diabetics must monitor their blood sugar levels themselves. Their insulin isn’t produced properly and/or doesn’t function like it should. Diabetics must inject insulin when blood sugar is too high, or eat something sugary if their blood sugar drops too low.

Carbohydrates trigger insulin because they are usually short or long chains of glucose, but depending on the type of carbohydrate or the glycemic index (GI) of that carbohydrate, you get a lesser or more powerful release of insulin. The index works on a scale of 0-100 based on how much the food raises your blood sugar after eating. 

Low GI foods (Complex carbs like whole wheat, vegetables and beans) are slowly digested and absorbed, gradually raising blood sugar, and high GI foods (white bread, candy, are digested and absorbed rapidly, quickly spiking blood glucose levels. Proteins also signal insulin, but to a much lesser extent, and fats have no effect on insulin release.

So, if you want to lose weight, you want to be in the fasted state. This is why intermittent fasting works, because even though you tend to consume the same amount of calories in a day as you would normally, you are just increasing the amount of time you’re in the fasted state and thus burning more fuel. Consuming more complex carbohydrates like whole wheat, beans, vegetables can reduce the amount of insulin released over time and the amount of glucose stored as fat.

If you want to gain lean muscle mass and/or restore glycogen supply (storage form of glucose, main fuel for powerlifters and sprinters), you want to be in the fed state to promote building and uptake, but you also want to be in the fasted state to keep that muscle lean. 

Most people eat before exercise in order to fuel up, and it’s smart to eat 1-2 hours before your workout. A small amount of simple sugars and protein, along with moderate amounts of healthy fats is ideal for a small spike of insulin that fuels you up and clears quickly. When you start exercising, whatever insulin remains will be slowly cleared so you can break down fuel you need to workout. This means that it’s not too problematic if you do eat a lot, but it will take a lot longer for you to burn off fat if you load up on carbs and protein (thus, insulin) right before your workout.

Your pre-workout fuel is not nearly as important as your post workout fuel. Recovery is crucial in boosting your muscle weight gain. The most important time to be in the fed state is immediately after your workout, within a half an hour to be exact. This is the time where your glycogen stores are low and your muscle fibres are probably battered and torn, so your body is already in panic mode. 

The muscles will rapidly absorb glucose, fats and protein, even without much insulin stimulation at this point. Feeding yourself some simple sugars to give that extra insulin boost increases that uptake even more. It’s absolutely essential you consume most of your protein at this time, because it will but taken up and used immediately to start building and repairing those muscles. 

Whatever your body goals are, being in different states and learning how to trigger insulin can significantly improve your results. Knowledge is power, and if you understand how your body works, you can make it work for you.

Works Cited:

1. American Diabetes Association. "Diagnosis and Classification of Diabetes Mellitus." Diabetes care 33.Supplement 1 (2010): S62-S69.
2. Borghouts, L. B., & Keizer, H. A. (2000). Exercise and Insulin Sensitivity: A Review. International journal of sports medicine, 21(1), 1-12. 
3. Holloszy, J. O. (2005). Exercise-induced Increase in Muscle Insulin Sensitivity. Journal of Applied Physiology, 99(1), 338-343.
4. Van Praag, H., Fleshner, M., Schwartz, M. W., & Mattson, M. P. (2014). Exercise, Energy Intake, Glucose Homeostasis, and the Brain. The Journal of Neuroscience, 34(46), 15139-15149.