They’ve been hailed as a miracle cure for obesity, helping 1.6 million Britons lose weight.

But there is a way to turn down the food noise, curb inflammation and lose fat for good - all without a single weight-loss jab.

The ‘zone diet’ is decades old. It was created by the American biochemist Dr Barry Sears in 1995 and designed to boost metabolism - it also promotes weight loss by suppressing hunger and preventing blood sugar spikes, just like weight-loss injections.

Its instructions are simple - stick to eating 40 per cent carbohydrates, 30 per cent protein and 30 per cent fat, and most of those carbohydrates should come from vegetables and low-sugar fruits.

Research has shown that sticking to this ratio can improve blood-sugar control, inflammation and waist circumference in those who are overweight or obese, according to a study in the American College of Nutrition journal.

The ‘zone diet’ has similar effects to weight-loss jabs, a nutritionist said (Getty/iStock)

The zone diet was one of the first to use hormones to aim for weight control, rather than just cutting down on calories, according to Rob Hobson, registered nutritionist and author of The Low Appetite Cookbook.

Weight-loss injections, also known as GLP-1 receptor agonists, work by mimicking the natural hormone which regulates blood sugar, appetite and digestion.

Just like weight-loss jabs such as Mounjaro and Wegovy, the zone diet triggers the GLP-1 hormone that tells your brain to switch off hunger, through its high fibre and protein content.

“Diets that are higher in protein and fibre, and lower in refined carbohydrates, tend to slow digestion, stabilise blood glucose and increase satiety,” Mr Hobson told The Independent.

“Protein and fibre both stimulate gut hormones involved in appetite regulation, including GLP-1, which helps explain why people often feel fuller for longer on this style of eating.”

Kim Pearson, a nutritionist who specialises in weight loss, explained how protein and fibre not only slow digestion, but also trigger gut hormones involved in satiety and blood sugar control.

“Protein is particularly effective at stimulating GLP-1, while fibre feeds gut bacteria that produce short-chain fatty acids, which can further support GLP-1 secretion. In that sense, eating this way can help reduce appetite and stabilise energy levels in a more natural way,” she said.

However, the diet is not equivalent to a GLP-1 medication as weight-loss jabs have a far stronger effect.

“Natural GLP-1 doesn’t last anywhere near as long as the synthetic injectable version - but that is not a bad thing! The key is regulating appetite and satiety, rather than completely shutting off the desire to eat as weight-loss drugs can,” Ms Pearson added.

Nutritionists also warn the zone diet theory is “over-simplified” and not a “magic formula”.

Mr Hobson explained dieters are probably just benefitting from eating more protein and vegetables, being mindful about portion sizes and eating fewer ultra-processed foods.

Eating whole foods, protein and plenty of fibre are all diet changes Ms Pearson supports for weight loss. She added: “For most people, long-term success comes from learning how to structure meals in a healthy yet enjoyable way that supports appetite regulation.”

Recent findings by researchers at the University of Oxford discovered that people on weight loss drugs such as Mounjaro and Wegovy lose weight during treatment. But they often regain it within 20 months of stopping the jabs, which is four times faster than traditional dieters.

In comparison, the study found that those who are supported to lose weight through healthier diets and exercise keep the weight off for about four years, implying that dieting could be more sustainable.

Doctors and nutritionists warn those who have lost weight using GLP-1 drugs need robust support to make lifestyle changes to maintain their progress, from exercise to diet advice.