Eat more fiber. This is a frequently repeated mantra in the halls of health and fitness. At Metabolic Effect we would agree it is one of the most important considerations in the fat loss lifestyle. But, it is also the most misunderstood.
To our way of thinking, there are only two types of carbohydrates: fiber based carbs and non-fiber based carbs. In the fat loss lifestyle it is imperative you know which is which, because fiber based carbs are a key tool for fat loss, while non-fiber based carbs will often inhibit fat loss.
To us, fiber based carbs are non-starchy vegetables and a few select fruits. Everything else we consider non-fiber carbs. To most people this is confusing. If that is true why do so many experts claim you should eat more whole grains for fiber? It is true that grains in general have more fiber than fruits and vegetables, but when it comes to fat loss that is not what matters.
For fat loss, you must consider the total sugar load relative to the fiber load. It is important to understand that to your body, sugar and starch are the same thing. That is because biochemically speaking they both turn to glucose. Glucose is the simple sugar used by your body to derive energy. Fiber is important because it slows the release of glucose into the body and blunts the negative hormonal response created. The problem is the body still has to eventually deal with the total glucose amount in a food whether the fiber is present or not. It is better if it can deal with it slowly, which fiber will help with, but too much starch/sugar in general is not helpful for fat loss. So, if you really want to maximize fat loss and minimize fat storing, then you should seek out carbohydrates that have the smallest amount of sugar/starch and the highest amounts of fiber. Vegetables, but NOT grains, fit this description.
This is a relative argument. More important than total amounts of fiber, is the relative ratio of fiber to sugar/starch. Consider processed white flour bread. This product is all starch with almost zero fiber. Compared to whole grain bread, there is no comparison in terms of fiber concentrations. Now consider vegetables and fruits. They have less TOTAL fiber than whole grains but more RELATIVE fiber (see the graph above to get a good understanding of these ratios). It is this low starch to fiber ratio that makes these foods better fiber sources. Even beans, which are considered one of the highest sources of fiber, from a total perspective, are still 2/3 starch. That is not a great ratio as far as fat loss is concerned.
Another benefit of fruits and vegetables over grains is the water content. Water provides bulk and aids in feeling full for longer. Grains are almost completely devoid of water while fruits and vegetables are loaded with it. This is why you can eat 4 or 5 servings of cereal and still be ready for more, but would feel completely satisfied with 2 apples or 2 cups of broccoli. Fiber is most beneficial when it is packed with water; the way it comes with fruits and vegetables. Fiber and water are synergistic together.
When you consider carbs in this new context, it becomes clear that the foods we used to think of as “high fiber”, actually are not. Their fiber to starch/sugar ratio make them relatively higher in starch and lower in fiber compared to other foods. Therefore, for the fat loss lifestyle you want to stick with the real high fiber foods, vegetables and less sweet fruits, and minimize the higher starch foods, which are everything else.