How long should I wait before eating seconds?

Q. I am always trying to lose weight but I struggle because I have a large appetite. A friend of mine said I should wait 20 minutes after my first helping of a meal, before I have seconds. I was just wondering why it needs to be 20 minutes?

A. Healthy Food Guide nutritionist Claire Turnbull responds:

When you have a meal, the food travels from your mouth via the oesophagus into your stomach. When your stomach is empty, it’s a bit like an empty balloon and when food goes into it, like air into a balloon, it expands to accommodate the food you have just eaten.

As your stomach expands and food starts to be digested and nutrients absorbed, a range of signals are sent to your brain that let it know you have eaten and, when you have had enough to eat, that you are full. Although your stomach may feel full as you are eating, it can take approximately 15-20 minutes for your brain to receive all the different satiety signals and hence know that you have had enough to eat.

If you eat quickly (which most people do), a problem can occur. If you finish your meal in, let’s say, less than 10 minutes, your brain won’t have time to register that you are full. So you can easily feel like you need more food in this time and opt for a second helping, even though your body probably didn’t need it.

With your large appetite and weight-loss goals, it is definitely worth eating more slowly and waiting longer before having seconds. There are other things you can do to tame your appetite, too. Fill up on non-starchy vegetables, which are packed with fibre, and include protein rich-foods in meals and snacks. Make sure you are getting enough sleep, too. Being tired can also make you want to eat more.