According to a new study, popular diet books vary considerably in their ability promote heart health. While some scored well for including hearty healthy foods, others barely got a passing grade. Nutrition expert Leslie Beck presents some insights into the study.

Q: How did this study work?

Given that having a wider waistline substantially boosts the risk of heart disease, an optimal weight loss plan should promote weight loss and a healthy heart. That only makes sense when the whole point of losing weight for many people is to improve health.

In the study, researchers from the University of Massachusetts Medical School rated eight popular diet plans based on their status on the New York Times Bestseller list for the past five years. Contenders included: the Atkins Diet (100-gram and 45-gram carbohydrate plans), the South Beach Diet (phases 2 and 3), the Zone Diet, the Ornish Diet, and the New Glucose Revolution.

Weight Watchers (high carbohydrate and high protein plans), the largest commercial weight loss plan, and the current U.S. government recommendation, the 2005 Food Guide Pyramid (MyPyramid), were also included in the comparison.

Scoring was based on seven dietary components strongly linked to protection from heart disease: fruits, vegetables, nuts and soy, ratio of white to red meat, cereal fibre, trans fat, and ratio of polyunsaturated fat (fish and vegetables oils) to saturated (animal) fat. Each factor counted for a possible 10 points; a perfect overall score was 70.

Q: Which diets came out on top?

While no diet achieved a perfect score, some significantly outperformed others in terms of heart health. The highest performing plans -- Ornish, Weight Watchers, High Carbohydrate and the New Glucose Revolution -- scored well due to the fact they included more fruits, vegetables and whole grains and contained less trans fat.

Here are the top four:

Rating weight loss diets
 Eat More, Weigh Less  92%
 Weight Watchers (high carb)  82%
 The New Glucose Revolution 82%
 The South Beach Diet, Phase 2 72%

Q: Which diets fared the worst for heart health?

The worst performers -- the Atkins Diet, the South Beach Diet and Weight Watchers High Protein --lost points because they were higher in red meat and trans fat and lower in fruit and cereal fibre. Over the longer term, the intake saturated fat combined with trans fat may put dieters at risk for heart disease. Here are the bottom four:

Rating weight loss diets
 Weight Watchers (high protein) 67.5%
 Atkins for Life (100g carb)  65.7%
 The South Beach Diet (phase 3)  65%
 Atkins for Life (45g carb) 60%

Q: So, what's your advice when choosing a diet?

There's no question that losing excess weight can improve your health. Even if you don't have high cholesterol or high blood pressure, achieving a healthy weight can reduce your future risk for developing heart disease (not to mention type 2 diabetes and certain cancers).

It's possible to lose weight with most diets -- at least for the short term. But since dietary change is meant to be long term, whether a diet helps maximize cardiovascular health should also be considered when choosing a weight loss plan. When shopping for a weight loss plan, consider the following to help you choose one that's friendly to your waistline and your arteries.

  • Does the plan exclude any foods or food group? A sound weight loss plan should include foods from all four foods groups. Foods that promote heart health should be emphasized such as fruit, vegetables, whole grains, high fibre cereals, legumes, nuts, fish and unsaturated vegetable oils.

  • Does the plan rely on specially purchased foods? Eating pre-packaged, pre-portioned meals requires little effort, but eventually you'll have to learn how to eat healthily in the real world. Skills such as label reading, healthy cooking, portion control, and navigating restaurant menus are keys to keeping the pounds off.

  • Is the plan based on realistic goals? Healthy weight loss diets promote a loss of one to two pounds per week. Women should eat at least 1,200 calories per day; men should eat at least 1,600.

  • Does the plan promote exercise? A weight loss diet should encourage 30 to 60 minutes of exercise most days of the week. Regular exercise reduces the risk of heart disease and makes it more likely you'll maintain your weight loss.

  • Is it good for your kids? If you're a parent, consider whether the diet promotes a way of eating that's healthy for your kids. If it's not good for them, it's not healthy enough for you. Finally, ask yourself if you would feel comfortable eating this way for the rest of your life. If not, it's a short-term solution that won't work.