Low-carb diets and their effects on your body
In the past several years, low-carb diets have become a popular way to lose weight fast, and the ketogenic diet is the most recent one. Would you like to know what effects these sort of diets have on your body? Here’s a little insight.
Less calories ingested = weight loss
The guiding principle of weight loss, whether it be a drastic one or a more progressive one, is calorie reduction. Bottom line, regardless of what foods you restrict (carbs, fats, proteins or any combination of these), it is the difference between the total calories ingested and the calories burned that count. This is called the energy balance . In a low-carb diet, it is clear that carbohydrates have been eliminated from your diet. If a proportionate increase of protein and fat does not take place, the body will be in caloric deficit and will have to draw on fat reserves (muscle or fatty tissue) to get the calories it needs.
Ketosis takes place
Carbohydrates are the main energy source of the human diet. They provide fuel to cells, to the brain and to muscle. When the human body does not get enough carbs for energy (i.e., when fasting or when on a low-carb (ketogenic) diet), it burns the glycogen reserves stored in muscle and in the liver. Once these short-term reserves are depleted, an alternative energy source is triggered. The liver must now extract energy from fatty acids, which produces a waste product called ketones. When enough ketones are present in the blood streem, the body is in ketosis (hence, the name ketogenic diet). In addition to helping you burn fat, ketosis can make you feel less hungry  by modifying hunger hormones, which can be helpful during the weight loss process. However, because muscle extracts energy more efficiently from carbs than from fats, it would seem that a carb restricted diet (inducing ketosis) causes a decline in physical performance and an increase in fatigue and perceived effort . If physical activity is a key componant in weight loss and is essential in maintaining muscle mass, low-carb diets are not your best ally at the gym.
Old habits die hard
Like any drastic dietary change, the low-card diet is practically impossible to maintain for life. If your diet restricts certain food groups to which you are accustomed (think starchy foods and desserts), you will no doubt crave them, whether it be after one week or after three months. Fact is, it has been clearly shown that short term drastic diets (no matter which one) do not work in the long term : the large majority will return to their old eating habits and end up gaining back all the weight (if not more).
Finally, the winning formula for weight loss is to modify your eating habits in such a way as to be able to maintain them for life. What we are promoting is a healthy, active lifestyle rathan than a short-term sacrifice.
- Sumithran, P., et al., Ketosis and appetite-mediating nutrients and hormones after weight loss. Eur J Clin Nutr, 2013. 67(7): p. 759-64.
- White, A.M., et al., Blood ketones are directly related to fatigue and perceived effort during exercise in overweight adults adhering to low-carbohydrate diets for weight loss: a pilot study. J Am Diet Assoc, 2007. 107(10): p. 1792-6.