The science-backed diet that a longevity expert says can beat weight-loss drugs – The Independent
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After a long, hot summer it’s time for a September reset as we ease back into work and normal life. In the first in a three-part series on how to switch up your diet and exercise routine, longevity expert Professor Valter Longo talks to Harry Bullmore about the diet that can naturally trigger higher levels of appetite-reducing GLP-1s
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The weight loss drug debate rages: are they good for us, and should people be using them?
Most weight loss drugs mimic a hormone called glucagon-like peptide-1 (GLP-1), which is released by the gut after eating to reduce appetite and cravings. You crave less; you eat less; you lose weight – and research shows these drugs do work in the short term. But side effects such as muscle loss have been reported, and most studies suggest people quickly regain lost weight when they stop using them.
This is why Professor Valter Longo, director of the Longevity Institute at the University of Southern California, wants most people to eschew weight loss drugs in favour of diets that naturally promote GLP-1 production.
“People think I’m going to tell them to eat less, but I always tell them to eat more,” he says. “In a world of Ozempic, what you want is a diet that makes your own GLP-1, instead of having to take pills. Now you’re less hungry, and your intestine and stomach feel full because you’re eating a lot of food.”
As many look to shake off extra pounds gained during holiday bad habits, the reset diet he recommends comprises a large volume of food but a normal amount of calories, as well as smart meal compositions designed to trigger the desired effects. And it should be tailored to the individual, Professor Longo stresses.
Eating well is not easy. Most people make an active effort to eat in a way they believe is healthy – restricting calorie intake, consuming fewer sugary drinks, etc. – yet still find their health and fitness goals slipping further away as time goes by.
“We always think, ‘Oh, it’s easy, just eat less.’ But that’s another misconception,” says Professor Longo. “After a while, your body starts to worry because there are too few calories coming in, so it switches into energy-saving mode. Now, counterintuitively, you may gain more weight by eating less.”
His solution to this is The Longevity Diet – an approach informed by research, while also learning from the Mediterranean and Okinawa diets. It encourages people to eat more, rather than less, while following a few simple rules.
Foods are mostly plant-based, with some fish and little meat. Protein targets are low by modern standards – 0.37 grams per pound of body weight per day, slightly higher if you are over 65 – and should mostly be obtained through beans, whole grains, nuts and seeds.
This approach provides optimal amounts of the essential amino acid methionine, which Professor Longo’s research suggests should be kept at a moderate level – too high and it accelerates ageing, too low and it leaves you susceptible to frailty. In mice, this diet increased levels of GLP-1 while avoiding the muscle loss and frailty often associated with the use of weight loss drugs.
Saturated fats should be limited and all eating is confined to a 12-hour window – for example, 8am to 8pm. Whole grains, nuts and nutritious foods such as fruits and vegetables are to be prioritised.
“Select ingredients that your ancestors would have eaten” is the overarching advice – foods high in fibre, sufficient levels of protein and unsaturated fats have all been linked with healthy longevity.
“An ideal meal would be to have 250g of vegetables, 250g of legumes, then maybe some starches – 70g of rice or pasta,” Professor Longo says. “That’s half a kilogramme of food. That’s a big meal.”
This is where the personalisation aspect comes in, he adds.
“The UK has its own version of this. People sometimes think we have always eaten in a certain way, but vegetables that were grown near your home used to be how most people ate.
“That’s why I don’t think the UK has to follow a Mediterranean diet. The UK should have its own version of The Longevity Diet that is more consistent with what your grandparents and great grandparents used to eat.”
Instead of pasta, you might have 70-80g of potatoes, he suggests. Rather than relying largely on legumes as your protein source, whole grains and fish could do the heavy lifting, while seasonal vegetables, nuts and fruit should fill the rest of your plate.
You can also employ trial and error to ensure this approach to eating works for you.
“You could start by eating 0.8g of protein per kilogramme of body weight per day, with a two-to-one ratio of plant-based proteins to animal proteins,” Professor Longo says. “That is a minimum approved by most of the world’s medical associations [and the latter ratio tends to contain optimal levels of methionine].
“…But if you’re doing resistance training and you’re still losing muscle, your amino acid [the building blocks of proteins] intake may be insufficient and you have to raise it a bit – just to 1.1g/kg, not the 2g/kg that some people have been talking about.
“And if you’re gaining weight, the starches and saturated animal fats are likely contributing to that weight gain, so you might need to reduce them.”
Read more: The enjoyable exercise better than walking for lifelong fitness
“GLP-1 drugs are getting so much attention, but there are better ways to lose weight which are grounded in longevity science,” says Professor Longo.
“Weight loss drug’s big mistake is trying to reach the end goal too fast, and that comes with lots of problems. They offer short-term effects. Every pharmaceutical company has told people, ‘You’ve got to stay on it to keep the effects because, as soon as you quit, you’re going to regain the weight.
“So you can see why it’s important to go with the diet and not with the drugs – because we already know the vast majority of people are not going to stay on the drugs for very long.”
His aim is to match the impacts of weight loss drugs with natural foods, crafting a sustainable approach you can stick with for life.
“A lot of people say, ‘I tried to lose weight with millions of different diets, but everybody told me to eat less and I couldn’t do it,” Professor Longo continues. “Here, we’re saying, ‘You don’t need to eat less, you need to eat more, and there are some tricks we can use to keep GLP-1 and similar hormones high and reduce fat naturally.”
This diet can also regulate insulin-like growth factor 1 (IGF1) levels and may also trigger greater release of the hormone-like protein fibroblast growth factor 21 (FGF21), he adds. The combined impact of this can slow the ageing process, help prevent cancer, better regulate energy and blood sugar levels, and promote fat loss.
“The real longevity medicine is not about injecting yourself and taking 100 pills a day,” Professor Longo says. Instead, he wants healthcare professionals to work together and recognise the matrix of hormones and health markers at play, then make dietary prescriptions accordingly rather than jumping to pharmaceutical interventions.
“For example, in our recent study we found that low but sufficient levels of the amino acid methionine – which is high in animal proteins but low in different plant-based proteins – allowed mice and probably people to keep their fat deposits low while maintaining muscle,” he explains.
“This inexpensive medical approach doesn’t exist right now, but I think it should be part of any health system. In the US, we’re close to 20 per cent of the GDP being spent on healthcare, but the healthcare quality is not among the top in the world.
“We spend a tonne of money on poor healthcare. People should demand this healthcare system that understands all of these moving parts, keeps you healthy and keeps you away from hospitals and drugs.
There are some situations where a weight loss drug may be appropriate, Professor Longo adds.
“If somebody who is obese comes to our foundation clinics and they’ve tried The Longevity Diet, they’ve tried our fasting mimicking diet and they’ve tried time-restricted eating, and after five years nothing has worked, I agree that GLP-1 drugs are probably a good option before going to bariatric surgery,” he says. “If you’re obese or diabetic, these drugs are a reasonable last option.”
“But that’s not how they are being used. We’re hearing about people who want to lose a couple of extra pounds, so they take the drugs because it’s easy. And that’s an illusion.”
Read more: The daily habits that actually improve your health and fitness, according to experts
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