While most diets may help people lose weight in the short term, people should pay attention to the long-term effects that diets could have on the heart, according to a new study.

The study, "A Dietary Quality Comparison of Popular Weight-Loss Plans," was carried out by researchers from the University of Massachusetts Medical School. It was published in the October issue of the Journal of the American Dietetic Association.

"Obviously, obesity is associated with an increased risk for cardiovascular disease," said Assistant Professor Yunsheng Ma, one of the study's authors in the report. "Optimal weight-loss plans should facilitate both weight loss and chronic disease prevention, specifically cardiovascular risk reduction."

The study took eight diets that had appeared on the New York Times bestseller list over the past five years and assessed their long-term effects on the heart.

"They were scored on seven dietary components that are strongly linked with protecting (people) from heart disease," nutrition expert Leslie Beck told CTV's Canada AM.

The study looked at the content of fruits and vegetables, nuts, soy, whole grains, cereal and fibre in the plans. The plans were also rated on their levels of trans fats and the ratios of white meat to red meat and polyunsaturated fats to saturated fats.

The highest performing diet plan in the study was Dr. Dean Ornish's low-fat, vegetarian "Eat More, Weigh Less" program.

Other diet plans that fared well in the study included "Weight Watchers High Carbohydrate" plan, the "New Glucose Revolution" and "The South Beach Diet, Phase 2."

"They all scored points for having lots of fruits and vegetables, more fibre and less trans fat," said Beck. "That's why they did well."

But the Weight Watchers high protein diet, "The South Beach Diet (Phase 3)" and the "Atkins for Life" 45 gram carbohydrate and 100 gram carbohydrate diets did not score as well in the study.

"They lost points for having more red meat, more saturated fat and of course less fruits and vegetables in the diet," Beck said.

Beck said that while it is possible to lose weight with most diets in the short term, the effect of the diet on cardiovascular health should be considered when choosing a diet plan.

Beck said a diet plan should be chosen that satisfies a number of criteria:

  • an exercise regimen should be incorporated into the diet plan;
  • food groups should not be excluded; and
  • realistic targets must be a part of the plan.

Additionally, Beck said that knowing how to measure portions is essential and the suitability of the plan for children was also important when choosing a plan.

"You've got to ask 'Is it good for your kids?' Because if it's not, it's not good for you, either," Beck said.