Our body uses glycogen as a primary source of energy. Glycogen is actually the storage form of glucose (carbohydrates) in animals and humans. It is stored in the liver and muscles. When there is no glycogen available, the body will reach for its secondary energy source - stored fat and muscle protein.
When you eat carbohydrates, your body stores them as glycogen in your liver and waits for your body to use them as fuel. When performing an aerobic activity, like walking or running on a treadmill, your body has the option of using glycogen stores or fat stores. The problem is that your body won’t use any fat stores until your glycogen stores are used up. On the other hand, during anaerobic exercise, like weight lifting, your body can only use glycogen as fuel.
We can't harp on this advice too much: Eat at least 1 gram of protein per pound of bodyweight every day. Your major protein sources should be lean meats (chicken, steak, turkey breast, tuna), egg whites (the yolks contain the fat, so discard most of them when you're trying to lose fat), protein powder (whey or casein) and low-fat cottage cheese. As for fat, limit it to 20%-30% of your total daily caloric intake.
To lose weight gradually or to maintain weight loss, "The Primal Blueprint" recommends you limit your carbohydrate intake to 100 to 150 g per day. This allows a wide variety of food choices and is best if you don't want to give up things like bread or high amounts of fruit or if you are an athlete. You can expect to lose 1 to 1-1/2 pounds of weight per week.
Unlike a high starch diet where the body burns the energy it needs from glucose in the starch, eating mostly protein forces the body to burn stored fat instead of glucose. This cuts down on the body’s stores of fat and not only do you begin to look better, you feel better as well. You will feel less heavy and you’re lighter on your feet. Carrying around lots of stored fat makes for a very sluggish feeling.
The order in which your body uses fuel is: glucose --> glycogen --> fat --> protein. Your body uses glucose and glycogen as the main energy sources. You use fat as the next energy source. The body rarely, if ever, breaks down protein and uses it for energy.
Two things happen to any excess glucose that your body doesn't use for energy right away:
- The extra glucose is converted to glycogen, a larger sugar molecule, and stored in your liver and muscles. This process is called glycogenesis.
- If your liver and muscles are already full of glycogen, and can't accept any more, the body then converts the excess glucose to fat and stores it in your fat cells. This process is called lipogenesis.
If your daily diet is lacking the proper amount of protein, your body's ability to make new body proteins slows down and you actually start to break down existing body protein (muscle) to supply the body with the amino acids that your food is lacking. This is the WORST thing that can happen. Because you sacrifice muscles, your fat burning machines, your metabolism slows way down. This results in your body burning fewer calories and fat. This is why and how you can lose muscle tone on high-carb diets. Protein is the ONLY macronutrient that builds and maintains muscles. Never skip eating protein at breakfast or lunch to save it for dinner. You will be greatly increasing your body's ability to store fat instead of burning it.
Your only stores about 2,500 calories as glycogen, but you likely have at least 70,000 calories stored as fat. Therefore, low-intensity exercise burns a high proportion of fat to conserve muscle glycogen for higher-intensity exercise, which requires quick fuel supply.
Some of you may be thinking, "I may eat a lot of starchy carbohydrates, but at the same meal, I am also eating protein and fat. Why am I just burning sugar and storing fat?" It's a good question, and it gets to the heart of the vicious cycle.
Let's assume that you are following the current dietary recommendations that tell you to eat more than half of your daily calories in the form of carbohydrate. You fill your plate with a cup or so of pasta, topped with meatballs, some tomato sauce and cheese.
From the minute the pasta is in your mouth, it begins to be broken down into simple sugar. Your body can only store a small amount of sugar at a time in the form of glycogen that is stored in muscle and liver. What's not stored as glycogen is burned off as quickly as possible, forcing you to burn sugar, but your cells can only burn so much off at a time.
I realize this was a lot of information and some articles may give the same information and some may slightly contradict others. There are so many different schools of thought, and various theories to follow based on the results you'd like to achieve. But I think it's good to read up on the subject and understand how carbs/sugars, proteins, fats, and even hormones, are connected. I know I eat too many carbs. I loooooove the simple sugars. It is something I'm working on and reading these articles for this blog has me realizing it's time to cut them down (again). I'm not a fan of completely eliminating things, but I do recognize that I need a lot less sugar than I have been eating lately.