From 2002 to 2011, 1615 participants in a 10-day residential dietary intervention had measurements taken for weight, blood pressure, blood sugar and blood lipids at baseline and seven days into the programme. At mealtimes, they were given free access to a completely vegan buffet of minimally processed plant foods, very low in fat (7% of total calories) and very high in carbohydrates (about 80% of total calories).
“The burden of Western disease can be dramatically reduced by eliminating animal-source foods and vegetable fats from the diet and replacing those foods with low-fat, plant-based foods,” the researchers wrote in Nutrition Journal, citing dips in mortality rates in Denmark and the UK following wartime rationing of animal products.
This retrospective analysis of the vegan diet programme’s results found a median weight loss of 1.4 kg, and significant improvements in blood pressure, blood lipids, and blood sugar. Those who were the most overweight at baseline had the largest favourable responses, the study’s authors found.
“This kind of dramatic, early success can be important for maintaining patients’ motivation to adhere to the diet,” they wrote. “These rapid results could also motivate physicians to prescribe diet therapy before resorting to the pharmacy for helping their patients.”
Meals were based on starches, including wheat flour products, corn, rice, oats, barley, quinoa, potatoes, sweet potatoes, beans, peas, and lentils, plus fresh fruits and non-starchy green, orange, and yellow vegetables. As well as the omission of animal products, no isolated vegetable oils were used either.
The study did not provide information on participants’ health beyond the residential programme, but the researchers said the long-term effectiveness and cost-effectiveness of such an intervention deserved further study. They added: “We believe that this simple dietary approach can improve patients’ health and ultimately reduce healthcare costs.”
Meanwhile, a study published in Circulation: Cardiovascular Quality and Outcomes, has suggested there is a lack of evidence for long term benefits from popular commercial diets, like the Atkins or South Beach plans.
The USDA has set an acceptable macronutrient distribution range, which is associated with the lowest risk of chronic disease. It says that health outcomes are closely related to the balance of fat and carbohydrate, but specifies an optimum carbohydrate range of 45-65% of total calories, and 20-35% of energy from fat.
Protein should provide 15-25% of total calories, the USDA says. Macronutrient intakes in this study were well outside of these recommended ranges.
The full study is available online here.
Source: Nutrition Journal
Vol. 13, Iss. 99 doi:10.1186/1475-2891-13-99
“Effects of 7 days on an ad libitum low-fat vegan diet: the McDougall Program cohort”
Authors: John McDougall, Laurie E Thomas, Craig McDougall, Gavin Moloney, Bradley Saul, John S Finnell, Kelly Richardson and Katelin Mae Petersen