So, do we really need all that glucose in our bloodstream to fuel the activities of our muscles and brain?
Public health authorities still recommend a carbohydrate-rich diet to achieve health (food pyramid). However, the increasing number of chronic disease patients indicates that carbohydrates might not be the ideal food for human beings. People who are overweight, diabetic, have heart disease, cancer etc. might consider reducing carbohydrates and sugar from their diet.
This is how it works:
As human beings, we are designed to burn either glucose (from sugar and carbohydrates) or fatty acids (from fat) for fuel. If carbohydrates are available in the bloodstream, it will be the primary fuel. When the bloodstream is depleted from carbohydrates, then the body turns to fat for energy.
The hormone insulin is required for the muscle to burn this glucose. If there is a glucose overload, there is a sudden insulin overload as well, which is rejected by the muscle. It is called Insulin Resistance: the muscle is unable to utilize glucose for fuel. As glucose is a valuable fuel, our body does not want to waste it, this extra energy slowly ends up in our fat tissues. This is called insulin sensitivity of the fat tissues.
Weight-gain will depend on:
The amount and type of carbohydrate consume
The length of the high-carbohydrate period.
Some genetics play a role: for instance, different people will secrete different amount of insulin to the same amount of carbohydrates.
It also depends on the relative sensitivity of the muscle and the fat tissues.
Insulin resistant muscle tissue: will reject the glucose as fuel.
Insulin sensitive fat tissue: will store glucose.
So, what happens if we don’t have glucose in our bloodstream, if we don’t eat a high-carbohydrate diet?
It is said that glucose is needed for the brain and the central nervous system. It is in fact true. But, glucose is not the only fuel and carbohydrates are not the only source of this glucose.
If we do not consume carbohydrates, then obviously the diet is rich in meat (protein) and fat. This prompts the liver to produce ketone bodies and will supply three-quarters of the energy needed for the brain. This is called ketosis and the diet is referred to as ketogenic diet. These ketone bodies are synthesized from:
The fat from our diet.
The fat from our fat tissues.
The remaining energy will be supplied by:
The protein in our diet: it will be converted to glucose
The glycerol from the fat we consume (I won’t go into detail here).
Weight-loss will occur once carbohydrates are restricted:
Insulin levels go down (Insulin is a hormone that tells our body to store the fat in our fat tissues)
When our body starts to burn fat instead of glucose as fuel.
This means that our body is perfectly able to run without carbohydrates. Population studies indicate that somehow populations living almost exclusively on meat and fat, did not suffer from chronic diseases as we do today. As sugar and carbohydrate became part of their diet, chronic diseases made their appearance. (Diseases of Civilization).
There are populations who are able to tolerate a certain amount of carbohydrates. But, the amounts we are consuming today, are overwhelming our body, and our body’s response is obesity and the related conditions.
Ilona Kasza is a Hungarian fashion designer living in Singapore. She is the creator of the BIG FAT BLOG where she writes about food and health topics.
