Low Carb Diets for Weight Loss

This month, my IOC (International Olympic Committee) sports nutrition diploma class started. It will take me two years to complete the diploma, and will be even more qualified to give advice to athletes. As I progress through the course, I will bring you the latest in what’s happening in laboratory’s all across the world. In fact, my professors for this year come from Scotland and Australia mainly.

Low carbohydrate diets have gone through waves of popularity. There was Atkins, The Zone, the ketone diet, and many more versions. For almost all athletes, this is not the diet for you. Carbohydrates are our most efficient source of fuel, and what we should be focused on. I like my athletes to have diets in the range of 50-65% carb, 20-30% fat, and 15-20% protein. Low carb diets look like 10% carb, 55% protein and 35% fat. Or some variance of those ranges. Protein is not really a fuel source, and only about 4-5% of protein is used for fuel. So, looking up at the ranges above, and knowing that protein isn’t a great fuel source, let me say again, low carb diets are not the best for athletes looking at improving performance.

So, what does the latest research show? That low carb diets, or even lower carb diets, can be instrumental in promoting weight loss. Who am I talking about here, this is a blog for athletes? Well…..It’s people like me. An athlete who is currently injured and unable to exercise. It’s for someone who uses November and December to take off some weight. It’s not for someone swimming, cycling or running 5-20+ hours per week.
Let’s look at some of the data. All calories are not the same. This seems strange, but its true.
First, let’s go through some basic science. Some of this will be simplified, just in case there are some biochemists reading.  What is a Calorie: the amount of thermal energy required to raise one gram of water by 1 degree Celsius. Why does this matter? Everything we do during the day requires our body to produce heat, and we measure how many calories we need to take in, based on how much heat we produce. This is also called metabolic rate, or your Metabolism. We are producing heat, and thus require calories to do things like digest food, create urine, etc. When we digest food, your metabolism will be raised for a certain time period. This is called the Thermic Effect of Food. TEF, typically accounts for 10% of your daily calorie expenditure.Now lets look at how fats, carbs and proteins break down.

  • Fats, or lipids, take about 2-3% of heat to breakdown.
  • Carbohydrates take about 6-8% of heat to breakdown
  • Proteins take about 25-30% of heat to breakdown

So, looking at these numbers, you can see that the more protein you eat, the more heat/energy it will require for your body to break it down, thus you are burning more calories. Also, protein helps with satiety, or keeping you feeling full.

Personally, I could never eat a diet composed of 10% carb to 55% protein. I love fruits and vegetables way too much to be able to cut that far down. I try to eat like a vegetarian, and a large quantity of meat or eggs isn’t appealing. There are other sources of protein, but to be eating 55% protein, you will most likely need to eat some meat. Applying this practically to me, I can choose higher protein foods, to replace higher carb foods. Instead of maybe carrots and humus for a snack, I could have some plain non-fat greek yogurt or low-fat cottage cheese instead. A simple and still healthy switch. My ratio might look like 40/30/30 which is closer to the Zone diet.

Remember, just because high protein food is good for you when losing weight, that does not mean high fat/high protein food is what you should be eating. Things like cheeseburgers and sausage are reserved for special occasions. And for those in heavier periods of endurance exercise, just try to eat at least 20g of high quality protein with every meal.

Another topic for later is, the Thermic Effect of Exercise. This is how with exercise we are raising our metabolism, and how long and how hard we should be going for. More another day.

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