Professor Gary Frost, Imperial College London
Feeling full is our body's way of telling us we've had enough, and that maybe reaching for that last wafer thin mint isn't the best idea. But often this feeling doesn't kick in until we've already overindulged, especially when dieting.
Researchers in London recently completely clinical trials of a new "secret ingredient", which can trick your body into thinking it has eaten more than it has by exploiting a system in place to avoid over-eating. Gary Frost from Imperial College London explained first to Kat Arney why we feel full when we overeat.
Gary - It’s really complicated and we don't quite understand at the present time. there's lots of different signals that occur in the gut and just after you eat, some of these are generated by nerves. Some of these are generated by hormones.
Kat - What sort of things? They just signals to our brain going, “You know what? Put the fork down.”
Gary - Absolutely right. they do exactly that. they send signals probably to specific areas of the brain, the hypothalamus and the brain stem. They tell your brain that you've had enough. But the brain can override that if it sees something that it really likes.
Kat - Tasty, tasty pie.
Gary - Absolutely right.
Kat - So, you're actually looking at how you can hijack this system to make us think that we are fuller and back away from the pie. What did you start looking at?
Gary - Well, we’ve known for some time that deep down in your gut, in the colon, there are special molecules that are developed there by the bugs that live there. These molecules can actually signal and cause a release of appetite regulating hormones from your colon and it’s that that we’ve been looking at, is that these very small fatty acid molecules that actually cause the release of these hormones that actually stop you eating.
Kat - So, it’s food getting to the bugs in our gut that then make this signal and stop me from eating.
Gary - That's correct. That's absolutely right. but unfortunately, where we currently live, the actual types of food, because these are dietary fibres, the amount that we need to actually do that, we just can't eat enough at the present time. it was different if you live in Africa or somewhere where you have a very traditional native diet. But in the western world, we don't eat close to enough to actually do that.
Kat - Tell me about how you're trying to hack this system, how you're trying to use these chemicals to make a way of making people feel fuller.
Gary - It takes a bit of clever technology which has been developed by our research partners in Glasgow where we take those molecules – so short chain fatty acids and we attach them to a dietary fibre. So, a dietary fibre can't actually be broken down by the enzymes in your small bowel. So, what it does, it means that the actual short chain fatty acids hitch a ride on the dietary fibre and they get all the way down into your large bowel, into the colon where the bugs then actually chomp up the dietary fibre and release the short chain fatty acid. That actually enhances the amount that's there and releases the actual hormone that actually reduces your appetite.
Kat - So, the idea is you could add this to food say, a pie, if you put this in with the pie filling then your pie would make you feel a lot fuller and you wouldn't want to eat so much of it.
Gary - Well, you seem to be a bit stuck on pies but generally, the idea that this has been developed as a food ingredient because obviously, what we want to try and do, because as you've just heard, weight gain in adults is so widespread, you've got to develop systems that are on a population basis. So, this is an attempt to do exactly that. it’s to develop a very safe food ingredient that will suppress appetite in people who are actually concerned about weight gain.
Kat - It does sound great, but where is this at the moment? Have you tested it in clinical trials? Are there any risks for example like, could you overdose on it?
Gary - Well, the paper that we released just before Christmas - all the testing was done in humans. So, we know that this works. That we see a reduction in weight gain over a 6 months period when humans are given this particular molecule. can you overdose? It’s like any dietary fibre. If you eat too much of it too quickly then you're going to get minor effects such as bloating. But if you're actually sensible about what you do, it has very, very few side effects.
Kat - Very briefly, have you actually tried it yourself?
Gary - Yes. We’ve tried it ourselves in the clinic as part of the volunteers and it does what it says really. It actually causes a short term suppression of appetite. So, you eat it and about 3 hours after you've eaten it, you feel more full.