Fourteen contestants from the TV show The Biggest Loser lost an average of 58 kg in 30 weeks. Six years later, they had put 41 kg back on, and their bodies were still burning about 500 calories a day fewer than you'd expect for their size.
That's the bad news about weight loss you've heard. The rest of the story is better. About one in five overweight people lose a tenth of their weight and keep it off for at least a year, and a registry of people who have kept off an average of 33 kg for more than five years shows exactly what they do. Ahead: the kind of food that makes you eat 500 calories more without noticing, what low-carb, keto and carnivore can promise, what happens when the weight-loss injections stop, and the four habits the long-term winners share.
1. Expect your body to fight back
Weight loss sets off alarms. In 50 people who lost an average of 13.5 kg, the hormones that drive hunger were still shifted a year later, and they still felt hungrier than before they started. The Biggest Loser contestants, who lost their weight at TV speed, show the other half: a metabolism that slowed and was still slow six years on.
Going slowly is no escape. When 200 obese adults were set to lose the same amount in 12 weeks or in 36, those who got there had regained about 70% of it nearly three years later, at either pace.
Science saw this coming long ago. In 1944, 36 young men in Minnesota volunteered to be semi-starved for 24 weeks, and lost a quarter of their body weight. They became obsessed with food, and stayed obsessed after they were allowed to eat again.
So the hunger after a diet is biology at work. Plan for it from day one, and it stops feeling like failure.
Before you start, decide what you'll eat when hunger hits hard, so the choice is already made.
2. Expect the plateau
Weight comes off slower than the maths promises. The body adjusts to eating less over months: about half of the eventual change in weight takes around a year to arrive, and the less fat you carry, the less the same cut in food takes off. A stall after the first few months is your body settling, and a sign to keep going.
A stalled loss still pays. In 3,234 adults at high risk of diabetes, a programme that aimed for a 7% weight loss and regular activity cut new cases of diabetes by 58% over about three years.
When the scale stalls, check your waist. The tape tracks the belly fat that the scale lumps in with water and muscle. It also gives you a target: your waist should measure less than half your height. A waist-to-height ratio of 0.5 or more means a higher health risk, and 0.6 or more a high one.
Measure your waist halfway between your lowest rib and the top of your hip bone, divide it by your height, and check it once a month. A makes it easy to measure the same spot each time.
3. Eat real food
"Obese" comes from the Latin obēsus, from a verb meaning to eat away. What's on offer to eat matters as much as appetite.
Twenty adults lived in a clinic for a month and ate as much as they liked from two menus, two weeks each. The ultra-processed menu was matched to the real-food one for calories, sugar, fat, fibre and salt. On it, they ate about 500 calories a day more and gained 0.9 kg. On real food, they lost 0.9 kg without trying. Nobody counted a calorie.
A quick way to spot ultra-processed food: the ingredients list includes things no home kitchen has, such as high-fructose corn syrup, hydrogenated oils, emulsifiers, flavourings and colours. Chris van Tulleken's is a whole book on what this food is and what it does to appetite.
Drinks count too. Sugar you drink slips past your appetite. Fifteen people had the same 450 calories a day as jelly beans or as soda, four weeks each. On jelly beans they ate less of everything else to match. On soda they ate as before, and gained weight. Juice, smoothies and milk are sugar in a glass too.
Diet drinks are no way out. The World Health Organization advises against sugar-free sweeteners for weight control, having found no long-term benefit for body fat.
Alcohol adds to the plate as well. Across 12 tests, people who had an alcoholic drink ate about 80 calories more food on top of it, and took in about 250 calories more in total than with an alcohol-free drink. The calories in the drink came on top of the food.
Water works the other way. Among 48 dieters aged 55 to 75, those who drank water before each meal lost about 2 kg more over twelve weeks.
For the next week, build every meal from things that were recently alive: meat, fish, eggs and vegetables.
4. Choose a way of eating you can keep
"Diet" comes from the Greek díaita, a way of life. The word got it right first.
Low-carb works, and so does low-fat, if you stick to it. When 609 adults followed one or the other for a year, the low-carb group lost 6.0 kg and the low-fat group 5.3 kg, a difference too small to matter. Both groups started from the same rule: cut the added sugar and white flour, and eat plenty of vegetables. Across 13 tests lasting a year or more, keto diets did a little better than low-fat ones, by about a kilo.
Carnivore, the strictest version, has yet to be put to a long-term weight test. In a survey of 2,029 people eating mostly meat, fish and eggs, their typical BMI fell from 27.2, in the overweight range, to 24.3, in the healthy range, though that's self-reported by enthusiasts.
A fasting window follows the same pattern. When 139 obese adults cut calories for a year, those who also kept all their eating inside an eight-hour window lost 8.0 kg and the rest 6.3 kg, a gap small enough to be chance.
If you take medication that lowers blood sugar, cutting carbs or fasting can push it too low. Make the change together with whoever manages your medication.
The lesson is the same for all of them: the diet that works is the one you'll still be eating next year.
Pick the way of eating you could happily keep for life, and give it three months before you judge it.
5. Put protein first
Protein is the most filling thing on your plate. When 19 people doubled the share of protein in their diet, from 15% to 30% of calories, they ate about 440 calories a day fewer without being told to, and lost 4.9 kg in twelve weeks.
It helps the weight stay off too. After 148 people lost weight, half of them ate extra protein for three months, 18% of their calories against 15%. They regained half as much, and all of it was lean tissue.
Start every meal with the meat, fish or eggs.
6. Keep moving while you lose
Dieting alone takes muscle with the fat. Across 52 tests in adults over 50, at least 15% of the weight lost was lean tissue in 81% of the diet-only groups. When exercise was added, that fell to 39%. Exercise on its own moved the scale only modestly in those tests. Its job is to protect your muscle while you lose, and to keep the weight off after.
Everyday movement counts too. When 16 volunteers were overfed by 1,000 calories a day for eight weeks, some stored ten times more fat than others. The difference came down to fidgeting, standing and moving about through the day.
Movement also blunts your genes. The best-known obesity gene, FTO, raises the odds of obesity by about a quarter for each copy you carry, and across 218,166 adults that effect was 27% weaker in those who were physically active.
Add three sessions a week of something that makes your muscles work hard, from brisk walking uphill to lifting weights.
7. Protect your sleep
Short sleep turns a diet against you. Ten overweight adults on the same reduced-calorie diet for two weeks lost 55% less fat and 60% more lean tissue when they slept 5.5 hours a night than when they slept 8.5, and they were hungrier.
Sleeping longer cuts what you eat. Eighty overweight adults who slept under 6.5 hours a night were either coached to stay in bed longer or left alone. The coached group slept about 1.2 hours more and took in about 270 calories a day fewer, with no diet at all.
Late meals work against you as well. When overweight adults ate the same meals later in the day, they were hungrier and burned fewer calories than on the early schedule.
Give yourself an eight-hour window in bed every night while you're losing weight, and eat your last meal early in the evening.
8. Handle stress without food
Stress sends some people straight to the fridge. When 59 women went through a stressful session in a lab, those whose stress hormone, cortisol, rose the most ate more afterwards than on a calm day, and they chose more sweet food on both days. The worse their mood after the stress, the more they ate.
When stress hits, walk for ten minutes before you open the fridge, and see whether you still want the snack.
9. Do what the long-term winners do
The gloomiest figures on dieting go back to 1959 and 100 patients at a New York clinic. Twelve lost 20 pounds (9 kg) or more, and two years later only two had kept it off.
Better news comes from the National Weight Control Registry. Its members have kept off an average of 33 kg for more than five years. They share a handful of habits: about an hour of activity a day, regular weighing, breakfast, and eating the same way on weekends as on weekdays. Their odds also improve with time: after two to five years of keeping it off, staying there gets much easier.
Friends and family matter too. In 12,067 people followed for 32 years, a person's chance of becoming obese rose 57% when a friend did, and 40% when a sibling did. That's a link, and friends share more than habits, but it's a good reason to find one person to eat well and move with.
Weighing earns its place. In 3,003 registry members, those who began weighing themselves less often gained 4.0 kg over the next year, against 1.1 kg for those who weighed more often.
Catch a regain early. Of the 1,483 registry members who gained any weight in a year, only 11% were back at their starting weight a year later.
Weigh yourself once a week, same morning, and act on the trend before a kilo becomes five. A keeps the record for you.
What fat burners deliver
Weight-loss supplements promise a shortcut. When reviewers went through 315 tests of 14 kinds of supplement and alternative therapy, only 52 were sound enough to judge, and just 16 of those found any difference in weight, from 0.3 to 4.9 kg. Spend the money on real food.
When the injections stop
The injections depend on the same habits. In 1,961 adults, weekly injections of semaglutide (sold as Wegovy) cut weight by 14.9% over 68 weeks, against 2.4% on a dummy injection. In the 327 followed for a year after stopping, two-thirds of the lost weight had come back.
Tirzepatide (sold as Zepbound and Mounjaro) tells the same story. After 36 weeks on it, 670 adults had lost 20.9% of their weight. Those switched to a dummy injection regained 14% over the next year, and those who stayed on it lost another 5.5%.
The medicine changes appetite while you take it, and the habits decide what happens after.
When the weight stays put
A stall is one thing. If the weight keeps rising while you do everything right, or refuses to move however long you give it, look for a hidden cause: an underactive thyroid, Cushing's syndrome, polycystic ovary syndrome (PCOS, which the NHS now calls PMOS), the menopause, or a medicine such as some steroids, antidepressants or beta blockers. Get checked, and never stop a prescribed medicine on your own.
No more starting over
Weight loss fails when the body's alarms meet a world of cheap, processed food and a plan too strict to live with. It lasts when you plan for the fight.
The contestants on that TV show were given a finish line. The people in the registry built a way of life, which is what "diet" meant all along.
Reaching your goal weight is the start. Decide today what you'll still be doing a year after it.
Tired and hungry again an hour after eating? How to Fix Blood Sugar Spikes Naturally — the carbs to cut first, and the ten-minute walk that flattens the rest.
Still hungry after a full plate? The Hidden Power in Every Bite: Why Some Foods Fill You Up — what makes a meal last until the next one.
Know someone about to start another diet? Send them this before they begin.
Disclaimer: This article is general information. For advice about your own health, talk to a qualified health professional.
Affiliate Disclosure: This article contains affiliate links. As an Amazon Associate, All For Life earns from qualifying purchases, at no extra cost to you. We only link to products we would recommend without the commission.
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