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Winning at the hunger games
special report future of DIETING
Winning at the hunger games Knowing how our bodies control appetite is allowing us to create more satisfying diet meals
THE steaming plate of fish balls in tomato sauce looks and smells appetising enough, but I hesitate to tuck in, and not just because it’s 10 in the morning. These processed balls are no ordinary food: they could represent the future of the weight loss industry. Think of diet food and what usually springs to mind is tiny portions of insubstantial fare. Not so for a range of foods designed to work by being more filling than usual – meaning that, in theory, you should eat less.
Super starch The super-satiating foods being put through their paces at the University of Liverpool in the UK – where I am today – and other places around Europe have been made possible because of our growing understanding of how our bodies control appetite. It’s not just the signalling between our brain and our belly that we are getting to grips with, but also the influence of the microbes that make our gut their home. The pay-off could be a range of ways to make it easier for people to control their weight. Not only could we choose existing foods more wisely, but soon we may be eating a range of super-filling products – apart from fish balls, other things on the menu include bread, yogurt, smoothies, soups and sauces. If the trials go well, such products could be on the shelves in the next few years. But is the plate of food in front of me really 14 | NewScientist | 20 June 2015
the future for healthy eating – or does it miss the point? Our feelings of fullness are governed by a complex mix of factors, including the physical feeling of our stomach stretching, and the chemical and hormonal signals the food triggers arriving in our brains. Foods high in protein and fibre are particularly good at this (see “Weighty questions”, opposite). Some food manufacturers have already started marketing diet foods that are supposed to keep people fuller for longer, based on these principles. But there may be ways to push our satiety buttons harder still, thanks to the growing realisation that certain types of carbohydrate are particularly good at sending fullness signals from the gut to the brain. The compounds are a type of starch, naturally present in certain plants, which cannot be broken down by the enzymes in our small intestine, where most of our food is absorbed. Only starchy foods like potatoes, pasta when this “resistant starch” and rice if they are cooked then reaches our lower bowel is it allowed to cool down. finally digested by the resident So could we create a wider bacteria, which release chemicals range of foods that help people called short-chain fatty acids. lose weight by adding resistant These chemicals send starch or other satiety-enhancing messages to the brain that ingredients? That is the aim of starch is reaching the lower gut the SATIN project – a consortium without being digested. “That of seven European universities tells the brain to slow up on the and 11 food companies. input,” says Stephen Bloom of With our gut microbes having Imperial College London, who such an important role in the helped discover some of these “Processed foods that are mechanisms. healthy – and make you eat Resistant starches occur less – will have a positive naturally in peas, beans and impact on people’s lives” lentils, as well as forming in John Lund/getty
Clare Wilson
break down of resistant starch, a crucial player has been a Belgian lab that aims to recreate the gut’s complex ecosystems. Five microbial soups stand in for the main chambers of the human digestive system: the stomach, small intestine and the three parts of the lower bowel. Mechanically chewed up meals are fed into the stomach, then tubes take the slurry to each flask in turn – the contents getting progressively browner. “It’s like having a person laying on a bench,” says Massimo Marzorati, of ProDigest, the firm that runs the system.
weighty questions A range of super-satiating foods are in development but you don’t have to wait until they hit the shelves to get the benefit of more filling foods. Which foods are the most filling?
As well as a meal’s physical bulk, there’s a strict hierarchy among the food groups: protein is the most filling, followed by carbohydrate – fibre is better than starch, which beats sugar – and lastly fat. So protein for breakfast, in the form of eggs or meat, is a good way to curb mid-morning hunger pangs. Plant proteins are just as good as animal-derived ones, says Alexandra Johnstone of the University of Aberdeen, UK. “Any kind of protein is very satiating.”
resistant starch can have some unpleasant side effects. Feeding our gut bacteria means they release carbon dioxide, and the short-chain fatty acids can irritate the bowel. The end result? Farting and diarrhoea. Fortunately, I suffer no such collateral damage – and Jason Halford, who helps run the Liverpool research, says those effects haven’t been showing up in their trials so far. Of course, the proof of the –Tuck in– pudding is whether the supersatiating foods actually help The set-up allows Marzorati’s people shed the pounds. Halford team to check that when resistant is reluctant to tell me how the starches are mixed into new trials have been going on that foods, they still do their job. They front until the results are have tested about 50 products so published. What he will say is that far. Several have made it into preliminary results from a small human trials to see whether they placebo-controlled trial of people help people control their weight – eating modified tomato soup and, crucially, whether the grub every day suggests that it does is any good. reduce the amount of other foods This is where the fish balls someone eats. in front of me, which contain I can’t help wondering, though, resistant starch made from carob if it’s worth spending all this beans, started out. Their texture money – €6 million so far – seems fine and they are tasty on developing yet more highly enough, although I can’t face a processed foods – meals that whole plateful as a mid-morning will be more expensive to buy snack. Good thing, too, as than their fresh plant-based
Is that why the high-protein Atkins diet works?
Partly, although there may be other things going on. Cynics say another factor is that eating so much meat becomes off-putting, so people just don’t want to eat as much. Are there any alternatives to maxing out on meat?
There’s a kind of carbohydrate called resistant starch that seems to pack an extra punch when it comes to satiety (see main story). It is found in beans, peas and lentils – as well as starchy foods that have been cooked and allowed to cool, such as potatoes, pasta and rice. Some health bloggers advocate adding sources of resistant starch, such as potato flour, to smoothies. Watch out
ingredients. “Eating natural foods is cheaper and more effective,” says Bloom, who isn’t part of the SATIN consortium. “The problem is that, by and large, people aren’t consuming them,” counters Halford. However, he admits that the foods in development won’t be a panacea to the Western world’s obesity problem. “But if we can develop processed foods that are healthy and benefit appetite control we can make a positive impact on people’s lives,” he says. Certainly, we haven’t had much luck at convincing people to turn their backs on the typical Western diet of white bread and junk food. Most dieters end up putting the weight back on, and more.
Weight watchers Gary Frost of Imperial College London thinks super-satiating foods are more likely to help people maintain a steady weight, rather than lose it. He is developing breads and smoothies based on a similar premise to Halford’s, only they are fortified with the short-chain fatty acids that are the gut bacteria’s output.
though, as too much can cause farting and diarrhoea. What about calories?
You need to think about calories and satiety, says James Stubbs of the University of Derby, UK. Imagine you want a snack – a chocolate bar has the same calories as three smallish bananas, for example, but that fruit would fill you up for longer. “The chocolate bar bypasses the normal satiety mechanisms,” says Stubbs. Any other tips?
Cut back on the booze – it actually makes you feel hungrier. “Alcohol is the only macronutrient that when consumed in moderate amounts actually stimulates the appetite,” says Stubbs.
Initial trials in people suggest foods containing it help reduce weight regain after dieting. Una Masic, who is involved in the Liverpool trials, thinks resistant starch shouldn’t be used as a quick fix. “A diet should be for life, not just a month,” she says. Even if people don’t want to buy modified meals, just knowing which natural foods are the most filling should help people design their own meals better. This is where a new satiation index comes in. “There are 30,000 foods out there, and there are big databases on them but they don’t tell you anything about how filling those foods are,” says James Stubbs of the University of Derby in the UK. Stubbs is working with UK weight loss firm Slimming World to develop a satiety quotient for many foods, based on studies that have measured how much people eat at a subsequent meal. He thinks that just as dieters check a food’s calories, in future they will also consider its satiety quotient. “If you can navigate towards foods that are filling then you can manage your weight better,” he says. n 20 June 2015 | NewScientist | 15
Winning at the hunger games Knowing how our bodies control appetite is allowing us to create more satisfying diet meals
THE steaming plate of fish balls in tomato sauce looks and smells appetising enough, but I hesitate to tuck in, and not just because it’s 10 in the morning. These processed balls are no ordinary food: they could represent the future of the weight loss industry. Think of diet food and what usually springs to mind is tiny portions of insubstantial fare. Not so for a range of foods designed to work by being more filling than usual – meaning that, in theory, you should eat less.
Super starch The super-satiating foods being put through their paces at the University of Liverpool in the UK – where I am today – and other places around Europe have been made possible because of our growing understanding of how our bodies control appetite. It’s not just the signalling between our brain and our belly that we are getting to grips with, but also the influence of the microbes that make our gut their home. The pay-off could be a range of ways to make it easier for people to control their weight. Not only could we choose existing foods more wisely, but soon we may be eating a range of super-filling products – apart from fish balls, other things on the menu include bread, yogurt, smoothies, soups and sauces. If the trials go well, such products could be on the shelves in the next few years. But is the plate of food in front of me really 14 | NewScientist | 20 June 2015
the future for healthy eating – or does it miss the point? Our feelings of fullness are governed by a complex mix of factors, including the physical feeling of our stomach stretching, and the chemical and hormonal signals the food triggers arriving in our brains. Foods high in protein and fibre are particularly good at this (see “Weighty questions”, opposite). Some food manufacturers have already started marketing diet foods that are supposed to keep people fuller for longer, based on these principles. But there may be ways to push our satiety buttons harder still, thanks to the growing realisation that certain types of carbohydrate are particularly good at sending fullness signals from the gut to the brain. The compounds are a type of starch, naturally present in certain plants, which cannot be broken down by the enzymes in our small intestine, where most of our food is absorbed. Only starchy foods like potatoes, pasta when this “resistant starch” and rice if they are cooked then reaches our lower bowel is it allowed to cool down. finally digested by the resident So could we create a wider bacteria, which release chemicals range of foods that help people called short-chain fatty acids. lose weight by adding resistant These chemicals send starch or other satiety-enhancing messages to the brain that ingredients? That is the aim of starch is reaching the lower gut the SATIN project – a consortium without being digested. “That of seven European universities tells the brain to slow up on the and 11 food companies. input,” says Stephen Bloom of With our gut microbes having Imperial College London, who such an important role in the helped discover some of these “Processed foods that are mechanisms. healthy – and make you eat Resistant starches occur less – will have a positive naturally in peas, beans and impact on people’s lives” lentils, as well as forming in John Lund/getty
Clare Wilson
break down of resistant starch, a crucial player has been a Belgian lab that aims to recreate the gut’s complex ecosystems. Five microbial soups stand in for the main chambers of the human digestive system: the stomach, small intestine and the three parts of the lower bowel. Mechanically chewed up meals are fed into the stomach, then tubes take the slurry to each flask in turn – the contents getting progressively browner. “It’s like having a person laying on a bench,” says Massimo Marzorati, of ProDigest, the firm that runs the system.
weighty questions A range of super-satiating foods are in development but you don’t have to wait until they hit the shelves to get the benefit of more filling foods. Which foods are the most filling?
As well as a meal’s physical bulk, there’s a strict hierarchy among the food groups: protein is the most filling, followed by carbohydrate – fibre is better than starch, which beats sugar – and lastly fat. So protein for breakfast, in the form of eggs or meat, is a good way to curb mid-morning hunger pangs. Plant proteins are just as good as animal-derived ones, says Alexandra Johnstone of the University of Aberdeen, UK. “Any kind of protein is very satiating.”
resistant starch can have some unpleasant side effects. Feeding our gut bacteria means they release carbon dioxide, and the short-chain fatty acids can irritate the bowel. The end result? Farting and diarrhoea. Fortunately, I suffer no such collateral damage – and Jason Halford, who helps run the Liverpool research, says those effects haven’t been showing up in their trials so far. Of course, the proof of the –Tuck in– pudding is whether the supersatiating foods actually help The set-up allows Marzorati’s people shed the pounds. Halford team to check that when resistant is reluctant to tell me how the starches are mixed into new trials have been going on that foods, they still do their job. They front until the results are have tested about 50 products so published. What he will say is that far. Several have made it into preliminary results from a small human trials to see whether they placebo-controlled trial of people help people control their weight – eating modified tomato soup and, crucially, whether the grub every day suggests that it does is any good. reduce the amount of other foods This is where the fish balls someone eats. in front of me, which contain I can’t help wondering, though, resistant starch made from carob if it’s worth spending all this beans, started out. Their texture money – €6 million so far – seems fine and they are tasty on developing yet more highly enough, although I can’t face a processed foods – meals that whole plateful as a mid-morning will be more expensive to buy snack. Good thing, too, as than their fresh plant-based
Is that why the high-protein Atkins diet works?
Partly, although there may be other things going on. Cynics say another factor is that eating so much meat becomes off-putting, so people just don’t want to eat as much. Are there any alternatives to maxing out on meat?
There’s a kind of carbohydrate called resistant starch that seems to pack an extra punch when it comes to satiety (see main story). It is found in beans, peas and lentils – as well as starchy foods that have been cooked and allowed to cool, such as potatoes, pasta and rice. Some health bloggers advocate adding sources of resistant starch, such as potato flour, to smoothies. Watch out
ingredients. “Eating natural foods is cheaper and more effective,” says Bloom, who isn’t part of the SATIN consortium. “The problem is that, by and large, people aren’t consuming them,” counters Halford. However, he admits that the foods in development won’t be a panacea to the Western world’s obesity problem. “But if we can develop processed foods that are healthy and benefit appetite control we can make a positive impact on people’s lives,” he says. Certainly, we haven’t had much luck at convincing people to turn their backs on the typical Western diet of white bread and junk food. Most dieters end up putting the weight back on, and more.
Weight watchers Gary Frost of Imperial College London thinks super-satiating foods are more likely to help people maintain a steady weight, rather than lose it. He is developing breads and smoothies based on a similar premise to Halford’s, only they are fortified with the short-chain fatty acids that are the gut bacteria’s output.
though, as too much can cause farting and diarrhoea. What about calories?
You need to think about calories and satiety, says James Stubbs of the University of Derby, UK. Imagine you want a snack – a chocolate bar has the same calories as three smallish bananas, for example, but that fruit would fill you up for longer. “The chocolate bar bypasses the normal satiety mechanisms,” says Stubbs. Any other tips?
Cut back on the booze – it actually makes you feel hungrier. “Alcohol is the only macronutrient that when consumed in moderate amounts actually stimulates the appetite,” says Stubbs.
Initial trials in people suggest foods containing it help reduce weight regain after dieting. Una Masic, who is involved in the Liverpool trials, thinks resistant starch shouldn’t be used as a quick fix. “A diet should be for life, not just a month,” she says. Even if people don’t want to buy modified meals, just knowing which natural foods are the most filling should help people design their own meals better. This is where a new satiation index comes in. “There are 30,000 foods out there, and there are big databases on them but they don’t tell you anything about how filling those foods are,” says James Stubbs of the University of Derby in the UK. Stubbs is working with UK weight loss firm Slimming World to develop a satiety quotient for many foods, based on studies that have measured how much people eat at a subsequent meal. He thinks that just as dieters check a food’s calories, in future they will also consider its satiety quotient. “If you can navigate towards foods that are filling then you can manage your weight better,” he says. n 20 June 2015 | NewScientist | 15