I read with interest your article in the New Haven Advocate website. Your basic premise is one with which the experts at the Pritikin Longevity Center absolutely agree; when it comes to weight loss, the fundamental law of calories-in versus calories-out is the gold standard.
But I feel that it is important that you understand another profoundly important part of our program.
Pritikin’s approach is to emphasize optimal health and well being, with weight loss coming as a wonderful side effect of eating and living according to our guidelines. (Our guidelines are, by the way, are very similar to the new recently released USDA guidelines. It’s nice to know the USDA is finally coming around to what we have been teaching for the past 30 years.) We do not believe the goal should simply be weight loss. After all, as that fundamental law implies, as long as you eat fewer calories than you expend, you will lose weight even if the weight loss comes from eating 1,500 calories worth of junk food every day.
Our goal is to set nutritional guidelines that maximize people’s health. Yes, we want to help people lose weight, but we also want people to have clear arteries and not suffer from diabetes, hypertension or heart disease. Unlike other programs, we have published over 100 articles in the all the leading peer-reviewed medical journals on the beneficial effects of our program on the 90,000 people that have been through our doors.
Knowing and respecting your expertise in nutrition, I would like to invite you to chat with our experts in nutrition so that you can understand what we do. I believe that you will find our approach to be one that is much more than just “low fat” or a “fad diet” and one that you could not only admire and tout…but also write about.
Dr. Novella’s Response:
Thanks for your letter. The length of my Advocate article did not allow for a detailed discussion of individual diets. I only had time to strike a basic theme – calorie reduction and regular exercise are the key, not radical changes in the food type. I wanted to get people to accept that weight loss is long-term hard work, and forget about claims for easy or quick answers.
I restricted my focus to weight loss in the Advocate article, but you are, of course, correct that heart health, diabetes, and overall nutritional must be considered in assessing any diet, not just weight loss.
I agree that the literature shows, in general, low fat diets are better than low carb diets, especially long term. However, most of the literature specifically on Pritikin is fairly short term (and I just reviewed the list of articles on your web page). The long term studies are retrospective and look only at low-fat in general, not Pritikin specifically. One of the other points in my article is that long term weight control and health is what’s most important. Getting healthy for 3 weeks is great, but can you maintain it. Most people don’t. Further, many of the studies are complicated by the fact that the intervention also included exercise. It is possible that regular exercise was the dominant, maybe even only, important factor in the improvements seen. There aren’t enough studies to separate out these variables, and those that due tend to favor exercise as the key to long term success.
Actually, the program with the best evidence for long term success is Weight Watchers, which also focuses on calorie reduction and regular exercise, but seems to be the most successful in training people to have healthy habits long term.
Also, at least early on, the Pritikin diet focused more on total fat reduction and did not adequately focus on reducing “bad” fat while maintaining “good” fat. Some of the published studies that show a lowering of total cholesterol also showed no change in the ratio of HDL to LDL. This may be due to the fact that good fat was lowered too much in the Pritikin diet, but also may be because the studies were too short term, and ratio changes come only after longer intervention. Exercise, for example, should improve the ratio. But, I acknowledge that the Pritikin focus on eating vegetables and reducing red meat would tend to result in a good ratio of fat intake, I still think there is an excessive and perhaps unnecessary focus on reducing total fat. Perhaps the center has updated their recommendations in light of new research. That would be a good thing.
So, I agree that the Pritikin diet in general is a good one, certainly much better than the low carb diets, and including exercise in the overall health program is good. However, long term data on whether or not people can stick to the program is lacking and I am not that impressed by short term results from intensive intervention. I would like to see the popular diets converge more on current scientific data, and emphasize calorie reduction and exercise more. I agree that some diets, like Pritikin and Weight Watchers, are farther along than others. There are also many meal replacement products that have evidence to support their effectiveness as part of any overall weight loss program.
Thanks again. I hope this clarifies my position. I would welcome any references or pdf’s of published peer-reviewed research for my files.