What controls my appetite?

HELEN TRUBY: So if we think about what controls your appetite, is it physiological, simply physiological, or does your mind actually play a role in it as well? It has to be a combination of the two. Obviously, your body’s physiology does what it’s going to do, and in terms of your gut hormones and things, then you are going to have a sensitivity to those gut hormones. We know that people who are obese compared to people who are lean seem to respond differently to those gut hormones, indeed. And that might, as we’ve discussed, might not help people who are already overweight maintain weight loss. Your mind is also important in the fact that we know that people eat in certain situations.

So some people who, for instance, might be regarded as emotional eaters will eat for comfort, or they will eat in circumstances where they perhaps eat far too much than they need to. And indeed, they know that they don’t need to eat that amount of food. So understanding ourselves as well, understanding our mind, what triggers us to eat, what triggers us not to eat, is really part of that process of learning about how you as an individual are going to be able to manage your weight. In our work with children who are overweight, we often talk to them about feeling hungry and trying to cue them into signals when they’re actually hungry.

And children who are overweight and have been overweight for a long time will often say they either always feel hungry or they never feel hungry. They simply eat, because food’s in front of them, or there’s seemingly a right time to eat. So there are aspects of being able to get more in tune with your actual appetite and satiety mechanisms. We don’t entirely understand how best to do that, but we do know that once people lose weight, they seem to regain some kind of sensitivity to understanding those signals about when they’ve had enough too eat or not.

So some of it is certainly physiological, but there is probably a large element of psychology around it as well in people being able to reprogram themselves as to what’s an appropriate amount to eat and when to eat it. And also, our environment is such an obesogenic environment. We’re always surrounded by food. We’re never more than 20 paces from a vending machine, for instance, and it’s very difficult in that environment to actually have some kind of restraint around food.

And I think we often need to learn to have some kind of restraint, but obviously, not become over-restrained, so we’re not eating enough, but restraint can be functional in an environment where we simply would all become overweight if we ate everything we wanted to. So other things that can affect you feeling hungry is the form of the food that you’re having your nutrient in. So in terms of if we eat solid food, such as a steak, for instance, or a piece of cheese, that’s going to stay in our stomachs for longer, and therefore, it helps us feel fuller for longer.

When we have our meals, such as drinks, so if, for instance, we were taking a meal replacement, we would find that that potentially leaves our stomach quicker, and therefore, people might feel a bit more hungry, and they seek more solid food. So some of the diet drinks that people use are quite effective in terms of maintaining or helping people lose weight, and indeed, we have evidence that people who stick to those do just as well as anyone else who sticks to any other diet. But some people find them harder to do.