Feeding and Diet

The relationship between weight, hunger and appetite

The ability to control your nutritional intake whilst maintaining a healthy balanced body weight depends on your understanding of the process that makes you feel the urge to eat. Food Consumption and Appetite

Based on leading ‘cutting edge’ authorities in nutritional science, the present schools of thought in the human performance institutes generally agree on three factors regulating food intake:

• The hunger centre, which is situated in an area of the brain called the hypothalamus.
• The appetite itself, which is located in the stem of the brain
• The satiety centre, which is connected via a neural system to the appetite and hunger centre.

Appetite Factors

Current scientific evidence reveals that the brain stem influences appetite, independent of the hypothalamus hunger centre. The hunger centre stimulates an individual to eat whilst food requirement is diminished by the satiety centre .The appetite also stimulates the eating mechanism whilst appetite is often referred to in the same sense as hunger. It includes and is influenced by, the time of day, sight and smell of food.

Appetite is Learned

However, the truth is, that appetite relates to the desire for specific types of food and eating experiences, instead of food in the general sense. Appetite is responsible for selecting both the quality and balance of the food as learned by an individual in his or her surrounding environment.

The Hunger Center and Appetite

It is the hunger centre that is responsible for the long term, metabolic, regulation of food intake over weeks and months. Our hunger centre maintains normal quantities of nutrient stores and controls the physiological manifestations of hunger.

The following factors influence our hunger centre:

• In the presence of lowered blood/glucose concentrations, hunger develops to increase feeding activity thus elevating those low blood/glucose levels until they are sufficient to cause the sensation of hunger to be eliminated by the satiety centre.
• When amino acids concentration in the blood decreases, hunger increases, although this effect is not as powerful as our glucose requirement.
• When the quantity of fat molecules in the body increases, our physiological hunger actually decreases.
• When we’re exposed to cold weather, we are physiologically stimulated to eat more as cold temperature effects on the hypothalamus increases our need to provide fat for insulation against the cold.

Appetite versus Hunger

• Hunger is a craving for food associated with a number of sensations including hunger pains or a tightness/ "gnawing" feeling in the stomach, general tension, restlessness and ‘light headed’ feelings
• Appetite, in contrast to hunger, is the short-term, environmental regulation of feeding from hour to hour over the course of a day. The appetite is concerned with the immediate effects of eating factors including salivating, tasting, chewing, swallowing, and the clinical condition of the stomach and internal organs.

Appetite, Eating Control and the Upper Gastrointestinal Tract Nerves

When you overeat and over-expand your abdominal cavity, nerves in the upper gastrointestinal tract produce signals to stop eating. This is particularly important in stopping excess consumption as in an overly heavy meal and illustrates well why drinking water before a meal or why having soup with one can significantly reduce total calories consumed. When these "eating factors" controlled in the brain stem have been satisfied, the hunger centre in the hypothalamus becomes temporarily inhibited.

Since complete inhibition of the hypothalamus doesn’t happen until both appetite and hunger are satisfied, you may feel like food again soon after you have eaten if your appetite has been satisfied but not your hunger. It then becomes clearer why many people still go ahead and eat more, even when they’re not actually hungry!

Using Appetite to Control Hunger for a Healthy Weight Status

The foundational principle for adequate eating is to use your appetite to control your hunger.

If you wait until you’re physiologically hungry before you eat, you may well consume two or three times the amount you actually need for adequate nutrition. Many people on this course, skip meals and then "pig out", as it’s comparatively easy to brush aside your appetite but virtually impossible to ‘fight off’ real clinical hunger. To stop this happening, try to eat nutrient balanced meals every day, thus avoiding yourself becoming physiologically hungry and literally using your appetite to control your hunger.

Hunger, Appetite & Satiety

Satiety, which is the opposite of hunger and appetite, provides a feeling of fulfilment in the search for food. Satiety occurs when your nutritional storage deposits, such as the fat tissue (adipose) and glycogen (blood glucose) stores are full. So the appetite is satisfied when your ‘learned’ nutritional needs are satisfied.

Satiety, Appetite and Balance Hunger

It is important to eat efficiently, balancing your hunger and appetite with your satiety. Eating nutrient-balanced meals to avoid hunger, and at the same time to fulfill your appetite with those positive eating elements which are the objectives of an adequate diet. You can learn to use your appetite to control your hunger.

If you eat foods with sufficient nutrients to prevent hunger, satisfy appetite, and balance energy, you can avoid any major nutrition-related disorders. The objective is to learn to eat nutritionally balanced meals which will avoid the onset of physiological hunger.

Eating within your calorie range is one the important principles related to adequate nutrition. If you don’t eat within your calorie range, it will be extremely difficult or virtually impossible to balance your nutrients.

By: Alan Gordon MSc. Biomechanics & Applied Human Movement. BSc. (Hons 1st) Sports Nutrition.