The Grapefruit diet was one of the first fad diets to be introduced to the public and became popularly known as the “Hollywood diet”.
There are many different variations of the diet but most versions involve eating grapefruit or drinking grapefruit juice with every meal.
The diet’s fans claim grapefruit contains “fat-burning enzymes” that help to burn off fat which leads to weight loss.
Supporters of the diet claim they lose weight in just 12 days, with some claiming they lost as much as 10 pounds.
The diet involves eating a protein-rich meal plan every day that involves eating grapefruit or drinking grapefruit juice at every meal.
The original version includes cutting back on sugar and carbohydrates including pasta, potatoes and rice. Some versions also cut calories to as low as 800 calories per day.
However, according to experts, there’s “minimal evidence” that grapefruit contains “fat-burning enzymes”.
Bridget Benelam, a nutrition scientist, from British Nutrition Foundation, exclusively told Express.co.uk that grapefruit “does not have any specific weight loss or fat-burning qualities so ultimately this diet only works if it makes you consume fewer calories”.
She added: “Any diet that helps you reduce calorie intake will help with weight loss and the key is finding a dietary pattern that works for you.
“Unfortunately, fad diets are usually not easy to stick to in the long term so that any weight lost will be regained.”
Abbas Kanani, a pharmacist at Chemist Click agreed and said while grapefruits are low in calories and highly nutritious, there’s “no evidence” of fat-burning enzymes associated with the fruit.
However, he said grapefruit contains compounds like naringenin which “might” influence metabolism and insulin sensitivity which could potentially play a role in weight management.
Evelina Sabonaityte, a clinical nutritionist with over a decade of experience, said grapefruit does contain vitamin C and antioxidants but there is “minimal scientific evidence supporting” the idea that it contains “fat-burning enzymes.”
She added: “In my practice, I often emphasise the importance of a balanced diet and not relying on a single food item for drastic results.”
Is the Grapefruit diet effective?
The experts said one of the reasons people may experience “rapid weight loss” on the Grapefruit diet is because it’s “highly restrictive”.
Evenlia continued: “Many versions of this diet advocate for low-calorie intake. But remember, rapid weight loss isn’t synonymous with healthy weight loss. Losing weight too quickly can deplete muscle mass, impact metabolic rate, and even lead to nutritional deficiencies.”
Dr Carrie Ruxton, a dietitian at the Fruit Juice Science Centre agreed there are “no magic weight loss properties” in grapefruits.
She also said the Grapefruit diet works simply because it’s very restrictive, so people end up eating fewer calories.
However, she warned that once they’ve finished the diet and go back to their normal patterns of eating, people tend to put weight back on.
She added: “To lose weight and keep it off, it’s more effective to take a long-term approach by eating a balanced diet, watching overall calorie intake, and exercising most days of the week.”
Abbas said the results can vary from person to person when it comes to the Grapefruit diet.
“If you rely solely on grapefruit or its juice for weight loss, it is unlikely to show significant results,” he said.
The Grapefruit diet: the final verdict
Grapefruit and its juices are healthy and contain naringenin, antioxidants and vitamin C which have a plethora of benefits.
Naringenin has been shown in clinical trials to lower blood pressure and cholesterol levels which is important for protecting against cardiovascular disease. Vitamin C can help target chronic inflammation.
Grapefruit is also high in fibre and water content which can help people feel fuller for longer and help them eat fewer calories throughout the day.
The popular fruit is good to include in a diet from a general health perspective but dieters should not focus solely on one food group or food item as they can miss out on balanced nutrition and could end up developing “nutritional deficiencies”.
Many people also don’t realise that grapefruit and its juice can interact with certain medications which could lead to side effects of the reduced efficacy of medicine.
Evelina said she always advises her clients that the “best diet” is one they can sustain in the long run.
She concluded: “The Grapefruit diet is restrictive and monotonous. It’s hard for most people to eat the same thing repeatedly and be deprived of other essential nutrients.”
It is recommended people visit their GP before starting a new diet or meal plan.