Tuck in (Image: John Lund/Getty)
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.
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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 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“). 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.
Some are special types of fibre that become viscous when eaten and fill up the stomach. Another group of such 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 when this “resistant starch” reaches our lower bowel is it finally digested by the resident bacteria, which release chemicals called short-chain fatty acids.
These chemicals send messages to the brain that starch is reaching the lower gut without being digested. “That tells the brain to slow up on the input,” says of Imperial College London, who helped discover some of these mechanisms.
Resistant starches occur naturally in peas, beans and lentils, as well as forming in starchy foods like potatoes, pasta and rice if they are cooked then allowed to cool down.
So could we create a wider range of foods that help people lose weight by adding resistant starch or other satiety-enhancing ingredients? That is the aim of the – a consortium of seven European universities and 11 food companies.
With our gut microbes having such an important role in the 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 , of , the firm that runs the system.
The set-up allows Marzorati’s team to check that when resistant starches or other types of super-filling fibres are mixed into new foods, they still do their job. They have tested about 50 products so far. Several have made it into human trials to see whether they help people control their weight – and, crucially, whether the grub is any good.
This is where the fish balls in front of me, which contain a super-filling fibre made from carob beans, started out. Their texture seems fine and they are tasty enough, although I can’t face a whole plateful as a mid-morning snack. Perhaps that’s for the best, because some of these modified fibres and starches can have untoward effects on the gut, namely an increase in farting.
Fortunately, I suffer no such collateral damage – and , 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 pudding is whether the super-satiating foods actually help people shed the pounds. Halford is reluctant to tell me how the trials have been going on that front until the results are published. What he will say is that preliminary results from a small placebo-controlled trial of people eating modified tomato soup every day suggests that it does reduce the amount of other foods someone eats.
I can’t help wondering, though, if it’s worth spending all this money – €6 million so far – on developing yet more highly processed foods – meals that will be more expensive to buy than their fresh plant-based 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.
“Processed foods that are healthy – and make you eat less – will have a positive impact on people’s lives”
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
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 idea as using resistant starch, only they are fortified with the short-chain fatty acids that are the gut bacteria’s output. Initial trials in people suggest foods containing it help reduce weight regain after dieting.
Una Masic, who is involved in the Liverpool trials, thinks these modified food 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 of the University of Derby in the UK.
Stubbs is working with UK weight loss firm to develop a satiety quotient for many foods, based on . 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.
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 . Plant proteins are , says of the University of Aberdeen, UK. “Any kind of protein is very satiating.”
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 though, as too much can cause farting and diarrhoea.
What about calories?
You need to think about both 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 all that fruit would fill you up for much 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.
This article appeared in print under the headline “Winning at the hunger games”
Article amended on 14 July 2015
When this article was first published, the named satiating ingredient in the fish balls was incorrect. This has now been changed.
