The amount of food we eat is influenced by various things like culture, availability of food, calorie-dense nutritionally poor foods, habit, cost of food, stress and emotion. We also eat when hungry. It is hard to resist the sensation of hunger. Hunger is the signal to our bodies to re-fuel, and it is regulated biochemically. Unfortunately, sometimes the biochemical system can be upset, leading to extra appetite for food even when we have actually eaten enough.
When things are working without a hitch, hormones signal to the brain to either stimulate or supress appetite. But when the system gets disrupted, hunger keeps on nagging. We eat more, the system gets more upset, we get hungrier, we gain weight, and so on.
There are many chemicals including hormones which communicate with the brain to regulate the system. A few of the key hormones involved are ghrelin, insulin, and leptin. Hormones provide controls and messages for the body’s cells and organs.
Ghrelin is produced in the stomach. An empty stomach produces ghrelin, which signals hunger to the brain. It is time to eat.
After eating, insulin is produced in response to increased level of blood glucose (sugar). It is the hormone that signals the body to store energy from food as fat. Thanks to insulin blood sugar is sent to our fat cells to be stored for later. If we eat foods that dump large amounts of glucose into the bloodstream (foods like added sugar, white bread or pototoes, or drinks like juice or sodas) then we get a much bigger amount of insulin released to send the glucose into our fat cells. Subsequently, there is a crash in blood glucose, which makes us feel hungry again.
When things are working properly, insulin levels go up after eating, and leptin is released from fat cells signalling to the brain that we have eaten enough.
But if we eat foods with added sugar and without fiber on a regular basis our bodies are constantly producing large amounts of insulin in response. This has the damaging effect of making the cells of our body resistant to the effects of insulin, which means we produce more and more insulin to compensate. This may lead to pre-diabetes, then diabetes.
With high levels of insulin comes high levels of leptin. Leptin tells us to stop eating so it should be a good thing. Unfortunately, it seems that with high levels of leptin we also become leptin-resistant, which has the effect of making us feel the need to eat more and expend less energy.
To keep your appetite functioning normally avoid eating anything with added sugar, minimize eating white bread, white rice, white pasta, foods made with white flour, and potatoes. Stick with high fiber, wholegrain foods. You will find that feelings of hunger decrease. If you want a snack between meals eat a few nuts or a piece of fruit.