First, let's talk about what is coming in. If the goal is to minimize the amount of glucose (sugar) that reaches the blood vessels, sweets must be avoided. Table sugar is sucrose which chemically is composed of two glucose molecules stuck to each other. It takes nearly no effort to split them in two. Compare that to fructose, the molecule that fruit contains. It is composed of one glucose molecule and another called galactose. For the same amount of food ingested, there will be half as much sugar in whole fruit than in sweets. In addition, fruit contains fiber, vitamins and other nutrients all of which are healthy. The fiber makes the body work harder to digest the food and thus delays how quickly the nutrients reach the blood stream. In addition to sweets, some foods have a much higher glycemic index than others. Think of the glycemic index as how much sugar a given food delivers to the blood vessels. Cereals are notoriously high, though the higher fiber cereals are much better than the others. Bread, pasta and potatoes are also high glycemic foods. Whole grains are always better than processed ones. The bran and fiber in whole grains makes it harder to digest and will therefore deliver less sugar to the blood stream. For more details about the glycemic index of specific foods, click here.
In addition to the types of food we eat, the amount eaten is just as important. Our body uses sugar to meet its metabolic demands. If too much glucose is delivered, it will get stored either in the liver as long chains called glycogen or be processed into fat stores. If small amounts of food are eaten frequently, total calorie consumption will not need to be decreased in order to keep the weight stable. In fact one of the worst things someone can do when trying to lose weight is to skip meals. When going too long between meals, the body does not receive the nutrients that it needs so it enters starvation mode. Signals are then sent throughout the body to turn down metabolism, lessening energy demand. In addition, cortisol is released from the adrenal gland. One of its effects is to decrease the sensitivity to insulin, thus raising blood sugar. It is best to have healthy food nearby during the day. Just a few grapes or a bite or two of carrots will keep down hunger and maintain the metabolism. Keep it small and keep it healthy.
Lastly, eating a large meal late in the evening prior to going to bed is a recipe for disaster. Very few of those calories will be metabolized. The exception is if you chose to exercise in the evening before eating. Exercise turns on a muscle enzyme called alcohol dehydrogenase. It is quite good at burning up glucose. It stays active in the muscles for 2-3 hours after exercising. If you are going to have foods with a higher glycemic index, the time to eat them is during this window of opportunity after exercise.