You've probably seen the government food pyramid, but it doesn't give you portion size, or tell you how small a portion really is. Portion size is really important if you are serious about maintaining your weight. For example, half a banana is a portion. Three ounces of beef or chicken, about the size of a deck of cards, is an appropriate serving of protein for low-fat chicken, meat, or fish. A half-cup of rice is a portion.
Most bagels are actually three to four servings of starch.
If you eat half a bagel in the morning you should not have that much starch again later in the day. When it comes to drinking soda, says Guber, nutritionists put a label on it. It is important to balance sugar in terms of maintaining weight. So don't overdo the sugar. People lose weight and think they are home free.