The basic process of hunger can be likened to a traffic light: Green means start eating, yellow cautions that you are nearing the fullness point and red means stop.
Our physiology is actually designed to give us the green, yellow or red light, which could theoretically end the whole calorie-counting business in favour of simply eating according to physical hunger and fullness. Unfortunately, the practice is not that simple. For one, distractions get in the way of physical sensations. Through our body signals “green light”, we might be stuck in a meeting or an hour away from dinner. And the red lights? We often run those altogether, eating way beyond the point of fullness or munching when we are not really hungry.
Would we be better off obeying physical signals rather than continually overriding them? Do those signals truly indicate what, when and how much we should be eating? Is your craving for sweets at the end of a meal psychological or physical? Read on to find out about the principles of hunger and fullness and how to use them in effective weight management.
Stop and Go Signals
Mechanisms that control eating behaviour fall into two very broad categories — “stop” signals and “go” signals. hunger and appetite are the big “go” signals, while satiation and satiety are the main “stop” signals. Using the stoplight analogy again, here is a primer on the way they work.
Hunger is a primarily physical sensation that drives a need to eat. Hunger signals can include a grumbling stomach or difficulty concentrating. Appetite is primarily a learned psychological desire to eat, such as a craving, that can occur with or without hunger. When you are already full from a meal, appetite comes into play when the dessert cart rolls around.
As you eat, a variety of physical indicators tell your brain when you have had enough. Nerve receptors in the stomach and hormones throughout the body are activated, as well as the satiety centres of the hypothalamus in the brain.
Satiation means you are full from the current meal and it is time to stop eating. Some foods, like protein, are more satiating than others, like fats. Satiety is how long you are able to stay full; in other words, how long the light will stay red before turning green again. It is worth noting that there are many factors that affect satiety. A long list of hormones and physical mechanisms trigger hunger and satiety. For example, low blood glucose and a hormone called neuropeptide Y (NPY) are thought to stimulate hunger. Conversely, hormones such as serotonin and cholecystokinin (CCK) and many nutrients in the blood contribute to satiety. Despite the laundry list of physiological hunger and satiety triggers, appetite is what most often determines how much we eat.
Some nutrition experts believe one answer to weight management lies in letting internal hunger and satiety cues determine what we eat rather than the external appetite cues. A hunger scale is often recommended to reconnect someone with his or her body’s natural hunger and satiety cues.
A hunger scale provides a language for communication, as opposed to relying on just adjectives. The first step is to become familiar with how your body communicates. When was the last time you felt something vaguely called hunger? Some experts recommend that you actually touch the parts of the body where you identify those feelings. Then think, when was the last time I felt some fullness? Where did those thoughts and feelings come from?
After you have clamped the basics down, start looking at 0-10 gradations, with 0 being awfully hungry and 10 being extremely full. Keeping a journal if when, what and why you eat is one way to start filling in the scale. For instance, if you are at a “2”, you may feel like you cannot focus on anything but the thought of food and you may generally feel confused and irritated. At an “8”, you may feel an uncomfortable pressure in your stomach and wish you had stopped eating sooner. Continuing with the stoplight analogy, you might have a green light to eat between 1-4, a yellow form 5-7 and a red light at 8.
Having said that, there is so much more to hunger — even though you might be physically full, you may still find yourself wanting more or feel like having some sweet and savoury at the end of the meal. Physical signals could theoretically regulate how much you should be eating, but in practice, cannot be fully accurate.
Furthermore, a person might also become frustrated in differentiating between a 7 and 8 or a 3 and 4. Some people may not experience 10 distinct levels, so it is up to you to fit the scale to your personal hunger experiences. Alternatively, you can lower down the range and use a 0-5 scale instead.