You’ve probably heard the phrase “We’re carb-burning machines!”
But we’re not.
Oh sure, our bodies will burn carbohydrates for fuel, converting them into glucose we use for energy. Our body converts carbs through
a process that is quicker and easier than how it converts other macronutrients, like fat and protein. But the preferred macronutrient for energy is fat.
There are good evolutionary reasons for this choice. But when we load up on carbs as we do by eating things like grains and sugars, we alter the levels and functioning of our enzymes and hormones to accommodate the extra load of energy and the deficiency of nutrients. So we get fat.
We know that when your body is working at a level that is NOT out of breath, you are burning mostly fats. That is, for every activity throughout your day — sitting, walking, even exercising at a moderate level — your body chooses fats to burn over carbohydrates. How much of your day do you spend in that zone? 99-100%?
Below VT1, fats are the primary fuel source, only small amounts of lactic acid are being produced, and the increasing cardiorespiratory challenge comes from a need to increase inspiration, not expiration. The body responds by increasing the amount of air inspired with each breath (tidal volume). When exercising below VT1, talking should not be challenging or uncomfortable. (Ace Fitness)
When I say “fat,” I’m not talking about taking fat from your cells. I’m talking fatty acids found in your blood. How those fatty acids get in your blood are both from fats broken down from your stored fat but also fatty acids you eat.
So you don’t need that Gatorade, energy bar, or pasta. It doesn’t fuel you; it fats you. Eat nuts.
It’s in the Numbers
Every cell in your body needs fat for its health. A gram of fat has 9 calories. A gram of carbohydrate has 4 calories. A calorie is the measure of energy supplied. No wonder fat tastes good to us. Evolution would likely select for the best energy source, especially when that source also provides necessary chemicals for every cell in our bodies.
And no wonder we’re all fat from eating empty carbohydrates (grains and sugars). Our bodies store them easier and get virtually no nutrition from them, driving us to eat more because our bodies are not getting what they need.
If you’re a high-performance athlete working frequently near the VT2 level (speed, power), you burn more carbohydrates than most of us and likely those empty carbs in the form of grains and sugars are not getting shoved into your fat cells. I can guarantee that’s no more than 3% of you reading this. And that doesn’t mean they aren’t damaging your hormones and organs.
Endurance, long-distance, or even moderate exercise lasting hours is not necessarily hitting the carbohydrate burning zone. In fact, more athletes in these sports are beginning to turn to using fats for fuel with great success.
The days of “carb-loading” with big spaghetti dinners are going away.
One note: carbohydrates are dense sources of nutrients and fuel when we eat them in the form of vegetables and fruits. Carbohydrates in the form of grains and sugars are empty. Low carb diets are good insofar as they emphasize elimination of the empty carbs, not all carbs.
If, along with other foods, you’re reducing the amount of vegetables you eat in order to lower calories, you’re doing the absolute wrong thing. If you want to focus on calorie restriction for weight loss, simply quit the grains. You’ll be losing nothing your body needs.
All the details at Mark’s Daily Apple.