Consequently, a myriad of hormonal signals act to prevent weight loss.
The act of eating also sends out signals to the body. Even early man needed signals, called satiety, to tell the brain when the stomach was full. These signals preserved a limited food supply and prevented sluggishness and vulnerability associated with eating too large of a meal. Leptin has a role in satiety, but the main hormones involved in telling the body to stop eating are hormones released from the stomach and intestine. These include cholecystokinin (CCK), as well as glucagon-like-peptide-1 (GLP-1) and glucagon-like-peptide-2 (GLP-2). These hormones are activated after eating, but take time to signal the brain to halt the desire to eat more. The key point to remember is that we need to eat quite slowly to allow these signals to work. Our western eating habits are bypassing these important signals, so most individuals eat much larger meals than desirable or even necessary. Thus, weight gain is not caused by eating the wrong foods or not exercising, although these are important; rather we eat too much food at one sitting bypassing satiety signals.
One might think that eating several small meals throughout the day (grazing or noshing) would prevent weight gain. Can many small meals insure that my satiety signals are released and received by the brain? These are good questions, but the answer is probably no. People who snack all day usually do not eat nutritional foods. Typically they don’t eat because they are hungry, they eat because they are bored/anxious/depressed. They go from slightly full to very full with each snacking episode and underestimate how much food they eat. Eating three regular meals a day ensures that you will eat only when hungry, focus on your food and develop conscious eating. Eating only when hungry at regular mealtimes will allow satiety signals to operate and lead to portion control.
What is the solution?
Americans rarely sit down for a leisurely meal. We eat on the run, in front of a television, at a fast food restaurant, in the car, in bed for a midnight snack, always while doing something else.