Hunger versus appetite

Defining the difference between real and learned hunger can lead to better lifestyle choices.

WHEN it comes to issues of lifestyle and health, there is still much to be learned. There are also areas of confusion, sometimes just in terminology, that clouds understanding, and sometimes advice. 

Look up a medical dictionary for example for a definition of ‘hunger’ and ‘appetite’, and they are basically the same thing (i.e. a physical sensation usually associated with a craving or desire for food – Mosby’s Medical Dictionary).

But look up an English dictionary and they are quite different, in ways that are important for anyone interested in the finer aspects of lifestyle-related health problems, like obesity.

The Macquarie Dictionary for example defines ‘hunger’ as: “The pain sensation or state of exhaustion caused by the need of food”. Appetite, on the other hand, is: “A desire for food or drink.”

It doesn’t take a degree in English literature to understand that ‘need’ and ‘desire’ are two separate things, and that a misunderstanding of this could be significant in any health prescription.

Basically, hunger is the biological need to have to eat. It is a constant, urging drive to seek out food, which doesn’t go away with distraction. 

Appetite on the other hand, is a learned desire to want to eat, that develops largely through learning. It can go away when distracted and is therefore generally easier to deal with than genuine hunger when trying to reduce one’s food intake. 

But how do you distinguish the two?

Genuine hunger can be rated on a scale from 1 to 8, where 8 is ‘ravenously hungry’ and 1 is ‘full to the point of wanting to throw up’. Anything beyond about 6 is likely to be genuine hunger, whereas anything less than 4 is just a learned need.

Appetite develops from experience. If it is the normal experience to eat a three course meal every day at a certain time, whether hungry or not, the appetite for a meal at that time is likely to increase – irrespective of hunger. 

Studies with obese and normal weight individuals in a controlled environment where the clock is sped up show that the obese eat when the clock indicates that it’s lunch time; the normal weight eat when they get hungry.

Snacks are probably even more importantly influenced by appetite. A cup of tea, coffee or a glass of beer for example, if accompanied by nuts, chips, or anything else that is enjoyable, will usually lead to a pairing of those two stimuli (classical conditioning). Ultimately, this means every time you have a drink, you’ll get a craving for that type of snack.

Kids given soft drink after a game of sport, or when they’re thirsty, can become conditioned to the effect that thirst equals soft drink, rather than, as it should, water. 

If a mid-afternoon hunger craving is satisfied with chocolate, the next time mid-afternoon comes around, there’s an increased chance of a chocolate craving, irrespective of whether genuine hunger is the driver. And the more times this is satisfied the greater the chance of a mid-afternoon urge developing.

Appetite is the simpler one of the twin drives to deal with. Studies have shown that if a supposedly hungry person is given a fright or sexually stimulated in some way, the desire for food often goes away. If the desire for food is still the over-riding drive, then it’s usually genuine. If not, it’s probably just appetite.

Hunger, on the other hand, is much more difficult to deal with. Because it’s biological, it needs to be satisfied, but this can be done in all the wrong ways, e.g. with high, energy-dense foods. The trick is to fool the body: Foods that are high in fibre, protein, low-glycaemic index content, and even water, tend to reduce the energy, or calories taken in, while satisfying hunger.

Explaining this distinction to people trying to reduce their food intake, such as in a weight loss program, is often revealing. Because of the availability of food, genuine hunger is rarely an issue in a modern society like Australia. But appetite certainly is an issue. 

And as Pavlov showed over 100 years ago, it’s not just the feelings, but the physiology that accompanies this, such as salivation in preparation for ingestion, that can influence total energy intake.

Tips for weight control

• Recognise the difference between learned appetite and genuine hunger
• Satisfy genuine hunger with low energy-dense, filling foods. With this method you can actually lose weight by eating more.