A new study released today in the Journal of the American Medical Association compared the Atkins diet, the Zone diet, the Ornish diet, and Weight Watchers in 160 people over the course of one year. The biggest finding is that many people can not stay on a diet for one year. In addition, most participants lost half their desired weight in the first three months.
From the USA Today article:
Findings in today's Journal of the American Medical Association:
• At the end of one year, about 50% had dropped out of the Ornish and Atkins plans; 35% had abandoned Weight Watchers and the Zone. About 25% stuck very closely to the four diets for a full year.
• At one year, about 25% of participants in each group had sustained a weight loss of 10 to 20 pounds.
• About 10% of participants lost and kept off 10% of their initial weight.
• For each group, at least one person had lost 30 to 60 pounds at one year.
• In general, dieters lost half their desired weight in the first three months.
• Those who had the greatest weight loss had the best improvements in cholesterol.
• A 5% weight loss resulted in 10% improvement in heart disease risk factors.
• Those who followed the Ornish diet lowered their LDL (bad) cholesterol the most.
• Those who followed the other three plans had the biggest increases in HDL (good) cholesterol.
Now, here is why so many people failed and why weight loss stopped after the first three months:
1. No exercise program. They lost weight for sure, but they lost muscle as well as fat because they were not weight training. With the loss of muscle comes a drop in metabolism, which means it becomes harder to lose weight because your body is burning fewer calories to support its weight. Bottom line: weight train to maintain muscle during diet phases.
2. Calories were not adjusted as the weight came off. Obviously, these people were losing muscle and their metabolisms were slowing down, which requires a drop in calories or an increase in exercise. Every dieter knows about the plateau - how it is dealt with determines long-term success or failure. These people hit the plateau at three months.
3. They were asked to follow the diet seven days a week, 365 days in a row. After the first month or two, if the weight is coming off, a cheat day every couple of weeks helps maintain some sanity in what feels like a hell of deprivation. A cheat day isn't a license to get "supersized" for 24 hours, but it is a break from the structure and a chance to have some cheat items (low-carb ice cream, breakfast cereals, a couple of doughnuts, a piece of cake or pie, a few cookies). Doesn't matter what you love, have some, but keep portion size in control and make sure you get exercise on that day, even if it's just a one hour walk with the dogs.
This study is a good first step in looking at competing diets to see which work. But until we look at the diets in people using them correctly, which means with exercising people, we really won't know how effective they are.
One last thought: the Ornish diet is still too low-fat, with only 10% of calories coming from fat, and too low-protein. It might be an effective emergency diet for those who are at high risk of heart attack, but as a diet for the general population it is rather behind the research. We need higher fat levels, coming from healthy fats like nuts and seeds, and we need more lean protein to support muscle health. Dr. Ornish hasn't kept up with the latest research, and as a result, his diet his highly flawed.
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