Difficulty: Challenger (Level 2)

Many people enjoy sweet drinks and deep-fried snacks. However, they are not the best for our health.

This is because of the brain’s reward system. When we do things that are good for us, like eating healthy food, our brain releases a special chemical called dopamine.

Dopamine is often called the “happy hormone” because it makes us feel good. It also encourages us to repeat the behaviour (see graphic).

However, the reward system can be tricked by harmful things that feel good. For example, junk food can trick our brains into thinking we are eating very little. In fact, we are eating a lot of calories in a short time.

Junk food also contains lots of sugar, salt and unhealthy fats. Eating lots of junk food for a long time can cause health issues. These include digestion problems, heart disease and obesity.

There are ways to overcome our cravings for these snacks. One way is to eat more protein. Protein digests more slowly, making us feel fuller for longer.

Getting enough sleep can also help us stay away from unhealthy snacks.

Content provided by the Hong Kong Science Museum