Benefits of diets do not last long
MOST popular diets really do work at first – but the benefits disappear after a year, a major study revealed yesterday.
From low carb and reduced fat to the Atkins and Zone diets, they all result in modest weight loss and improved health, particularly blood pressure, but the positive effects appear to wear off after 12 months.
A team of international scientists based their findings on a study of 21,942 overweight or obese adults with an average age 49 who were all on popular diets.
Some were following a macronutrient regime – based on the ratio of fats, carbohydrates and proteins consumed – while others were on branded plans or the Mediterranean diet, which involves lots of whole grains, fish and olive oil.
Analysis showed low carb and reduced fat diets resulted in similar weight loss – of between 9lb and 11lb. These diets also lowered blood pressure after six months when compared to a usual diet.
Atkins, Dash and Zone diets had the largest effect on weight loss among named diets – between 7lb 11oz and 12lb 2oz.
Blood pressure in participants who followed these diets also decreased after six months. But weight loss diminished for all plans after 12 months. And the benefits for cardiovascular health essentially disappeared for all regimes, except the Mediterranean diet.
None of them significantly improved levels of “good” cholesterol or C reactive protein – a chemical linked to inflammation – at six months. Dr Helen Truby, of Monash University in Melbourne, Australia, said the extensive range of popular diets analysed “provides a plethora of choice but no clear winner”.
She argues the focus should shift from the specific choice of diet to how best to maintain weight loss.
“As national dietary guidelines fail to resonate with the public, taking a food-based approach and encouraging individuals to eat more vegetables, legumes and whole grains and less sugar, salt and alcohol is sound advice,” she added.
“We may learn more from understanding how commercial diet companies engage and retain their customers, and translate that knowledge into more effective health promotion campaigns.”