The appetite-suppressing diet that blasts fat and reduces inflammation

Want to switch off hunger, curb inflammation and lose fat for good – without weight-loss drugs? Long before Ozempic entered the conversation, there was a diet that promised similar effects.

The Zone Diet was one of the most talked-about eating plans of the 1990s, endorsed by Hollywood stars including Jennifer Aniston, Demi Moore and Renée Zellweger, embraced by athletes and followed by millions worldwide. Critics dismissed it as a celebrity fad, but many who adopted it back then still follow it today – and claim they are leaner, fitter and healthier than ever.

Created by the American biochemist Dr Barry Sears, the Zone Diet was designed to keep the body’s metabolism in a state where it works more efficiently. Dr Sears originally developed it to control inflammation and reduce the risk of heart disease. His father, a world-class athlete, died aged 53 after multiple heart attacks, as did other close relatives.

Followers soon discovered that the diet also promoted weight loss, largely by suppressing hunger and preventing blood-sugar spikes. A study in The Journal of the American College of Nutrition found that the Zone Diet could improve blood-sugar control, waist circumference and markers of inflammation in people who were overweight or obese.

Dennis Sullivan, 78, lost more than 20kg on the diet and still competes in road cycling races most weekends, often against men decades younger. “In my late 50s, I weighed around 93kg and was heading for type 2 diabetes,” he says. “When I started following the Zone, my hunger disappeared and the weight came off. Today, I weigh around 74kg, and my blood markers are what my GP calls teenage territory.”

So how do you enter the Zone – and should you try it?

What is it?

At its simplest, the Zone Diet is about balancing protein, carbohydrates and fat at every meal to keep blood sugar steady. It is a moderate-carbohydrate approach – higher in carbs than keto or Atkins – with a 40:30:30 split of carbohydrates, protein and fat. However, the diet recommends that carbohydrates come mostly from vegetables and low-sugar fruits, such as raspberries and kiwis, with no more than one serving of wholegrains per day. High-sugar fruit and vegetables, including butternut squash, parsnips and tropical fruit, should be avoided, along with starchy foods such as bread and pasta.

The diet allows low-fat sources of protein, for example lean chicken, turkey and fish, but advises avoiding fatty meats such as bacon and sausages, as well as full-fat dairy. Unsaturated fats, from sources such as extra virgin olive oil, avocado and nuts, are encouraged, as they help the body absorb nutrients and fight inflammation.

“Just as drugs need to be taken at a therapeutic dose, there’s a precise balance of protein and carbohydrates that makes your metabolism function more effectively,” Dr Sears says. “Once you hit this zone, you lose fat, gain muscle mass, perform better mentally and physically, and live longer.”

He argues that staying in this metabolic zone also helps to control the chronic, low-grade inflammation linked to insulin resistance, weight gain and metabolic disease. This is because the balance of protein and carbohydrates should prevent blood-sugar spikes that trigger inflammation.

The benefits

Reduced inflammation

When Dr Sears’s bestselling book Enter the Zone was published in 1995, the idea that diet could influence inflammation was considered radical. Today, it is widely accepted.

“The Zone Diet was one of the earlier diets to highlight chronic, low-grade inflammation as a driver of metabolic disease,” says registered nutritionist Rob Hobson, author of The Low Appetite Cookbook. “We now know it plays a role in conditions such as type 2 diabetes, cardiovascular disease and insulin resistance. In that sense, it was ahead of its time.”

Fans report tangible anti-inflammatory benefits. Lisa Bentley, 56, adopted the diet when she was a professional triathlete. “For years, I relied on anti-inflammatory drugs to manage a chronic injury, but once I started following the Zone approach I was able to come off medication entirely,” she says. “My energy levels also shot up, my lean muscle increased, body fat dropped and my race times improved.”

Followers monitor whether they are “in the zone” by tracking three blood markers linked to metabolic health and inflammation: the triglyceride-to-HDL cholesterol ratio, long-term blood sugar control (HbA1c) and omega-3 levels.

Better appetite control

For many people, the first noticeable effect of the diet is that hunger disappears. According to Dr Sears, balancing protein, carbohydrates and fat at every meal helps the body shift from fat storage to fat burning, meaning the brain receives fewer signals to eat. “A properly balanced Zone meal should control hunger for four to five hours,” he says.

Eating more protein also stimulates natural satiety hormones in the gut, helping you feel full for longer. “Calorie restriction only works if you’re not hungry,” says Dr Sears. “The diet triggers the GLP-1 hormone that tells your brain to switch off hunger – just like Ozempic.”

Nutritionists say the appetite-suppressing effect is plausible. Hobson explains: “When people follow the Zone Diet properly, it often works because it encourages adequate protein intake, fewer refined carbohydrates and better fat choices – all things we already know support satiety, weight control and metabolic health.”

Sustainable weight loss

Weight loss on the diet tends to be slow and steady. “Most people lose around a pound of fat every two weeks,” says Dr Sears. “It’s real, sustainable fat loss, rather than the rapid water loss often seen on very low-carbohydrate diets.”

One study comparing four different diets found that the Zone Diet resulted in a mean weight loss of 6kg over 12 months, around 1.2kg more than the low-carbohydrate Atkins diet, with adherence playing a key role. Average weight loss was greater among those who completed the study, with some participants losing more than 10kg on the Zone Diet.

The relatively high protein and fibre content also helps to preserve lean muscle mass during weight loss. “You maintain, and even increase, muscle mass while losing fat,” says Dr Sears.

“There’s nothing magical about the Zone Diet,” says Sullivan. “It’s simply sensible eating – enough protein to stay full, plenty of colourful, non-starchy vegetables, and a dash of healthy fats.”

How to follow the Zone Diet

The Zone Diet does not involve weighing food or constant calorie counting. Instead, it focuses on achieving the 40:30:30 split at every meal.

This comes down to three simple principles: prioritising protein, filling most of your plate with non-starchy vegetables, and adding small amounts of healthy fats.

To make it easier, Dr Sears recommends the “hand-eye” method, using visual cues to balance meals. “Roughly one third of your plate should be protein, two thirds non-starchy carbohydrates – mainly colourful vegetables – with a small amount of healthy fat,” he says. “Snacks follow the same principles.”

For those who prefer numbers, Dr Sears suggests meals of around 400 calories, containing 30g of protein, 40g of net carbohydrates (total carbohydrates minus fibre) and under 12g of fat.

A typical day’s diet for Dr Sears might include an egg-white omelette with vegetables, or yoghurt with berries and nuts. Lunch and dinner usually feature a palm-sized portion of protein, several cups of colourful vegetables and a splash of oil.

“The Zone Diet is designed to be followed for life,” he says. “If you fall out of the zone, you simply get back in at the next meal.”

What about supplements?

Alongside the Zone eating plan, Dr Sears recommends supplements of fish oil (omega-3 fatty acids) and polyphenols, both of which he describes as anti-inflammatory.

“Omega-3 fatty acids are needed to produce powerful anti-inflammatory hormones,” says Dr Sears. “Without adequate dietary levels, cellular inflammation increases. Polyphenols help repair damage caused by insulin resistance.”

The downsides

For others, the Zone Diet’s structured approach can feel restrictive and time-consuming. “Nutrition science has largely moved on from rigid macronutrient prescriptions,” says Hobson. “The real goal should be building healthy eating habits that people can sustain for life.”

Dietitian Raquel Britzke agrees. “Long-term success is more about consistency and food quality than following a strict macronutrient formula,” she says.

Nutritionists also point out that while the Zone Diet shares many principles with well-studied eating patterns – such as the Mediterranean diet, which prioritises vegetables, fish and healthy fats – the latter has stronger long-term evidence for heart health and disease prevention.

Verdict

Nutritionists generally agree that the Zone Diet’s core principles are sound. “Overall, it’s a well-structured and balanced approach to eating,” says Britzke. “It encourages healthy food choices and can help support weight loss, reduce inflammation and improve metabolic health.”

Experts stress that it is not magic. “The benefits do not come from a precise macronutrient ratio or any unique metabolic effect,” says Britzke. “Most of the positive results are driven by calorie control, improved food quality and a reduction in ultra-processed foods – factors shared by many balanced diets.”

The Zone’s structure may suit people who prefer clear rules, have blood-sugar issues or rely too heavily on refined carbohydrates. “For some, it can provide a useful stepping stone, helping to re-establish what a balanced diet looks like,” says Hobson.

The diet may also appeal to athletes. “Adequate protein and stable energy intake can support weight management and recovery,” says Hobson. “However, those with higher training volumes may need more carbohydrates than the Zone allows.”

[Source: Daily Telegraph]