Sunday, September 12, 2021

Sugar Is Not Your Enemy

When can I drink Coke again?
Those of you who know me well know that I have a sweet tooth. I love eating chocolate and drinking Coca Cola. However, now that I'm not able to do much exercise over the next 6-8 weeks after my accident last week, I definitely won't be eating much sugar!

There is a huge difference between consuming too much added sugar when not exercising and fueling your exercise with sugar. This always confuses athletes, myself included previously. So let me try to explain this.

Too much sugar in our diet can definitely harm our health, but consuming carbohydrate, including simple sugars can be beneficial to your athletic performance. During intense exercise and in the latter stages of a long endurance session/ race, when our muscle glycogen gets low or depleted, bananas, Coca Cola, gels and other concentrated sources of simple sugars get into our bloodstream and muscle cells much quicker. Some of you must have experienced this while on the verge of bonking and getting a sugar boost when you consume an energy gel. 

This then presents a dilemma for some of you who want to fuel high performance and simultaneously reduce sugar intake.

Carbohydrates include whole grains, fruits, vegetables, processed grain, rice, noodles, pasta, table sugar (sucrose) and monosaccharides (fructose and glucose).

When a food contains extra or "added sugar", it means that sugar that was not naturally present in a food or ingredient but was added during preparation or cooking, then you have to be careful. These are mostly in packaged foods although it goes by names like high fructose corn syrup, cane juice crystals, muscovado, brown rice syrup etc.

So when doctors or dieticians warn about health risks associated with consuming large amounts of sugar, they are not referring to carbohydrates, but excessive added sugar.

Excessive consumption of added sugar, also known as 'free sugar' is the problem and it is associated with obesity, *insulin resistance, Type II diabetes, cardiovascular disease and **other health problems.

How is this different from consuming sugar while exercising? During prolonged exercise (greater than an hour at least), simple sugar is useful, effective and does not come with risks and problems mentioned above. This is also true (although to a lesser extent) immediately before and after exercise.

The problems associated with simple sugar are tied to consuming it when you are at rest (or not exercising). Since your body needs to do something with the energy in the sugar you are consuming when you're not active enough to burn it, your muscles are still full of glycogen and you cannot store it, your blood sugar levels stay elevated longer and the excess is stored as fat.

When we exercise, our bodies use carbohydrates differently. Our muscles use glucose to produce energy and the amount of glucose they transport from our bloodstream into our cells increases, without needing insulin. 

Kipchoge monitors his sugar levels

Since exercise reduces blood glucose levels, insulin secretion decreases and glucagon increases. Glucagon does the opposite of insulin, it helps free glucose from its storage form (glycogen) in muscle cells and the liver to increase blood glucose levels. All that in simple terms means that during exercise the sugar you ingest does not cause your insulin levels to spike.

After a hard, long exercise session (> 60 mins), both muscle and liver glycogen levels are low, there is an opportunity to quickly store sugar (this can be Coca Cola, banana or even prata) as glycogen. This is when you can consume simple sugar (until your glycogen stores are replenished) without the ill effects described above.

So now you know, you do not have to avoid added or simple sugar during exercise and perhaps immediately after a long intense session or race, but that does not mean you should ONLY consume added or simple sugar while exercising. Complex carbohydrates and other real food that contains fiber, fat and protein are all parts of a sound nutrition that our body needs.

So, when added sugar does not serve a useful function (like exercise), and this is usually more than hour before or after exercise, you definitely should be eating real food, without added sugar.


Burke LM (2004). The IOC Consensus On Sports Nutrition 2003: New Guidelines For Nutrition For Athletes. Int J Sp Nutr Ex Metabolism. 13(4): 549-552. DOI: 10.1123.ijsnem.13.4.549

*Since added sugar is absorbed quickly, our blood sugar levels spike up quickly which leads to insulin being release rapidly to remove sugar from our bloodstream. This can lead to insulin resistance over time where more insulin needs to be produced before sugar is being absorbed. Over time insulin resistance leads to Type II diabetes.

**Other health problems include affecting leptin levels, which affect perception of hunger. When there are lots of leptin in the bloodstream, we feel less hungry. When we have low leptin levels, our brain thinks we are running low on energy and increases our appetite. Consuming too much sugar leads to leptin resistance whereby high leptin levels in the blood does not signal satiety and we either eat more before feeling full or feel hungry soon after finishing a meal.

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