Diets that involve cutting out most carbohydrates are just as safe and effective as low-fat diets, according to a study published in the New England Journal of Medicine. The Mediterranean diet, which includes plenty of fibre, fresh vegetables, fish, and olive oil, was also given the thumbs up.
The research was carried out by an international team of scientists from Israel, Germany and Canada. The study involved 322 moderately obese people who were put on three different diets and closely monitored over a two-year period. The first group were put on a low-fat, calorie restricted diet; a second on a Mediterranean-style low-calorie diet and a third group on a low-carbohydrate diet with no set calorie restriction. The volunteers decreased their total daily calorie intake by similar amounts.
All the dieters lost weight but those on the low-carb diet lost the most – 4.7kg (10.3lbs); they were closely followed by those on the Mediterranean diet – 4.4kg (10lbs). The low-fat diet was found to be the least effective with volunteers losing only 2.9kg (6.5lbs) over the two years. Most of the weight was lost by all the groups in the first six months.
The low-carb diet was also best for lowering levels of bad cholesterol while all three diets resulted in improvements in liver and inflammation function.
The dieters were helped by the fact that special meals were provided in the staff canteen at the Nuclear Research Centre in Israel where the study was carried out. The drop-out rate was extremely small with 85 percent of volunteers still following the diet by the end of the second year.
‘Clearly, there is not one diet that is ideal for everyone,’ said Dr Iris Shai, who led the study, ‘We believe that this study will open clinical medicine to considering low-carb and Mediterranean diets as safe effective alternatives for patients, based on personal preference and the medical goals set for such intervention.’
Atkins diet debate
This research reopens the debate about diets like the Atkins diet, which allow plenty of protein such as meat and eggs but cut out carbohydrates like bread, rice and potatoes. These diets are also high in fat, leading to concern among doctors that they may increase the risk of heart disease and kidney problems.
‘The problem with low-carb diets like the Atkins diet is that they are so restrictive that they reduce the chances of getting a good spread of nutrients,’ says Ursula Arens, spokesperson for the British Dietetic Association, ‘Eating very little carbohydrate also forces the body to change the way it produces energy and results in the production of chemicals called ketones which need to be removed from the body putting additional strain on the kidneys.’
The Mediterranean diet has always been a favourite among health professionals and dieticians. This sun soaked diet, stuffed with health boosting foods like tomatoes, fresh fish, olive oil and red wine, has been shown to protect against a whole range of illnesses including heart disease and cancer.
‘You don’t just have to eat food from the Med to be on a Mediterranean style diet,’ says Arens, ‘Think about sourcing fresh produce from your area. The key is to cut down on dairy – replace butter with plant oils – eat lots of fresh fruit and vegetables and replace red meat with chicken and fish.’