High-protein food diets – such as the Atkins Diet – actually increase the risk of putting on weight and even dying for people at high risk of heart disease, suggest new research. The Daily Telegraph reports that a study of 7,000 men and women found those eating diets high in protein had a greater risk of gaining weight in the long-term, compared to those with other dietary habits.
Although diets high in protein have become increasingly popular, there has been mixed evidence about their efficacy, and fears they could increase the risk of heart disease. The aim of the new study was to assess the links between high-protein consumption, body weight, and death, among people with risk factors for heart disease, such as obesity, type 2 diabetes and high blood pressure.
Spanish researchers analysed data from a trial involving 7,447 men aged 55 to 88 and women aged 60 to 80 between 2003 and 2009. None had heart disease at the start of the study, but all were at risk of it because of their weight or a health condition. Dietary protein was assessed using a food questionnaire over an average of five years.
The study found that higher total protein intake was associated with a 90% greater risk of gaining more than 10% of body weight when protein replaced carbohydrates. There was a slightly higher risk of weight gain among those who had replaced fat with protein, the study found. Higher total protein intake was also associated with a 59% greater risk of death when protein replaced carbs, and a 66% increased risk of death when protein replaced fat.
Study leader Doctor Jordi Salas-Salvado, of Rovira i Virgili University in Reus, Spain, said: "Higher dietary protein intake is associated with long-term increased risk of body weight gain and overall death in a Mediterranean population at high cardiovascular risk. At the moment, no evidence supports the use of high-protein diets as a strategy to lose weight long-term."
Salas-Salvado said that the mechanisms underlying the relationship between high-protein diets and weight gain are still unknown, but that it could be because protein affects the hormone system which influences appetite. Alternatively, those prone to going on diets could be more likely to eat more when the regime came to an end. The increased risk of death linked to high protein diets could stem from an increased risk of kidney disease, and changes in glucose and insulin metabolism, he said.
The study concluded: “A higher consumption of animal protein was associated with an increased risk of fatal and non-fatal outcomes when protein substituted carbohydrates or fat.
“Higher dietary protein intake is associated with long-term increased risk of body weight gain and overall death in a Mediterranean population at high cardiovascular risk.”
[link url="http://www.telegraph.co.uk/news/health/news/11589897/Atkins-diet-increases-the-risk-of-weight-gain-study-suggests.html"]Full report in The Daily Telegraph[/link]
[link url="http://www.clinicalnutritionjournal.com/article/S0261-5614%2815%2900091-6/abstract"]Clinical Nutrition abstract[/link]