The key here is that you must be eating in a Zone balanced way (40-30-30) in order for the fat burning to take place. Otherwise most of your dietary fat will be stored away in your fat cells, inexorably increasing your body fat year by year. This is the dilemma that most Americans face today as they scratch their heads wondering why they are not losing weight as they eat all those non-fat products like rice cakes, pasta, bread, and cereal.
Let’s see why this happens.
First certain assumptions must be made.
1. Eating a carbohydrate loaded meal will increase your blood glucose. I don’t think anyone would disagree with that.
2. A rapid rise in blood sugar will stimulate the pancreas to squirt extra insulin into the blood in an attempt to lower the glucose to a safe level.
3. High insulin levels block carnitine from bringing fatty acids into muscle cell’s mitochondria to make energy. The FA’s are therefore turned away, reform into triglycerides and re-enter the blood stream.
4. Meanwhile, the elevated insulin stimulates lipoprotein lipase which helps transport the extra fatty acids into the fat cells.
5. The biochemical mechanism for this effect on the fat cells is not thoroughly understood although we believe that insulin causes the fat cells to be less sensitive to normal levels of circulating epinephrine. Epinephrine normally would encourage the breakdown of triglycerides in the fat cells and cause them to release free fatty acids into the blood stream for use as energy fuel but since this is not happening, more FA stays in the fat cells than exits.
Think of insulin as a storage hormone, it makes all the cells into a one way street: it packs away the carbs into the liver and muscles while at the same time keeps the fat cells in the storage mode.
High levels of insulin dulls the fat cell’s ability to convert their stored fat into free fatty acids that can be used by the body as fuel.
I think you can begin to see what is happening already with the fat in your diet. It hasn’t got a chance to be burned for energy, it is busy being stored away by insulin.
4. Now let’s see how lower carb eating effects the picture.
If you lower your percentage of carbohydrate in the diet you will maintain a lower insulin level. This will increase the fat cells sensitivity to epinepherine which will encourage them to release their stored body fat.
At the same time low insulin levels produce higher glucagon levels. Glycogen acts to elevate another hormone, Hormone Sensitive Lipase (HSL) which mobilizes fatty acids out of the fat cells to provide more energy for the muscles. By eating low carb, you train your body to favor fat burning hormones. (HSL)
It is not a lower level of fat in the diet that stimulates the fat cells to disgorge their stored fuel, it is the ABSENCE OF EXTRA CARBOHYDRATES.
In other words: FAT DOES NOT MAKE YOU FAT, CARBOHYDRATES DO.
5. Let’s look at a typical scenario of fat loss at 1 1/2 lbs per week. This amounts to 750 cals per day. That is the amount derived from 83 grams of fat per day. But since you are already eating around 50 grams of fat in your diet, the total amount of fat you need to burn per day to lose 1.5 lbs per week is 133 grams (the 50 from the diet and the 83 from the fat cells). This is about 1200 cals of energy derived solely from fat.
Now, 50 grams of dietary fat daily divided by 3 grams per block = 15 blocks. When you add 15 blocks of Protein and carbs to the fat your total daily caloric intake is only about 1365. But since your are burning 750 cals in body fat, the total calories used daily is 2115, which is close to what is suggested by the ADA, etc. This is how Zone burns fat while still maintaining adequate caloric needs.
So lets look at some actual numbers. Using a 15 daily block zone diet (40-30-30), This is a total of 1365 cals. 30% from fat means you eat 45 grams daily of dietary fat. This is NOT a high fat diet, that is considered a low fat diet.
30% from protein is 102 grams daily. This is just slightly higher than the ADA recommendation which I may add is based upon the average, sedentary (SICK) population.
40% carbs is 136 grams daily, just enough to keep the fat burning TCA cycle operational, avoiding ketosis and muscle wasting but low enough to avoid insulin elevation and encourage fat burning hormones to elevate.