London - Dieters beware: not all calories are created equal, say experts.
Instead of obsessively counting numbers, they believe we should be focusing on what type of foods we eat – and that fat may actually protect us against weight gain.
Nuts, olive oil, fish and full-fat milk are among the foods that could help keep you slim, despite their high fat content.
In contrast, supposedly healthy low-fat foods may be the real diet villains as they leave us hungry and wanting more.
Dr Sean Lucan, of the Albert Einstein College of Medicine in New York, said that focusing on calories may “mislead and harm public health”. Writing in the journal Public Health Nutrition, he said that two foods may have very different effects on the body, despite containing the same number of calories.
For instance, protein fills us up more than other foods, while refined carbohydrates such as white bread, chips and white rice may leave us hungry or craving sweet foods.
Dr Lucan said this means we should focus on the type of food we are eating, rather than its calorie content. He said: “A calorie’s worth of salmon (largely protein) and a calorie’s worth of olive oil (purely fat) have very different biological effects from a calorie’s worth of white rice (refined carbohydrate) – particularly with regard to body weight and fatness.”
Some fats, he added – such as those in nuts, olive oil, dairy products, oily fish and avocado – may actually protect against weight gain. He warned dieters often replace fatty foods with refined carbs. These are lower in calories, but may alter hormones in such a way that we eat more and become so lethargic we don’t want to exercise. In fact, there is evidence that refined carbs actually whet your appetite instead of satisfying it.
In one study, a group of youngsters was told they could eat as many crisps as they wanted, while a second group was given cheese.
Both were equally hungry – but those given the crisps ate more than three times more calories.
Dr Lucan reasoned that if calories were all important, the children given the fatty, calorie-dense, cheese should have eaten more.
He said: “Substantial evidence now implicates foods that are low in fat, and thus relatively low in calories, like potatoes, white rice and sugary beverages, in the development and persistence of obesity and related diseases.
“Conversely, evidence is mounting to exonerate higher-calorie foods that are rich in fat like nuts, oily fish and olive oil and even foods high in saturated fat, like dairy products.”
However, dieters still can’t eat what they want. Many breakfast cereals and low-fat yoghurts fall foul of Dr Lucan’s theory, as well as less healthy foods such as fried fish, crisps and sweets.
Tam Fry of the National Obesity Forum agreed that food quality is key and counting calories causes “all sorts of problems”.
He added that although some experts are arguing over whether fat or sugar is worse, a small amount of each is key to a balanced diet, as well as portion control. - Daily Mail