Ron Rosedale, MD has devised a “powerful program based on the new science of leptin.” “Finally — the ultimate diet for fast, safe weight loss, lifelong health, and longer life…” He suggests it will prevent or improve high blood pressure, diabetes, heart disease, osteoporosis, arthritis, and a host of other ills. He repeats the CAM canard that “doctors only treat symptoms” and claims that his diet corrects the underlying cause of obesity, premature aging, and many diseases. That underlying cause is hormone (leptin) dysfunction. His is essentially just another low carb diet, only with more fat and less protein than other versions. His recommendations are ridiculously elaborate and are not supported by good evidence. His diet extrapolates from basic science, is based on speculative hypotheses, and has never been tested to see whether it works and is safe, much less whether it is superior to other diets.
If this sounds vaguely familiar, it should. He is doing what so many proponents of fad diets have done in the past, and he does it poorly. His book is a puerile effort compared to Gary Taubes‘ Good Calories, Bad Calories; Taubes at least marshaled an impressive mass of scientific data, presented a cogent argument, and ultimately acknowledged that more studies would be needed to test his recommendations.
What is leptin?
Leptin, discovered in 1994, is the “satiety hormone” that controls hunger. When we eat, leptin levels rise and let us know when it is time to stop eating. There were early hopes that leptin supplements would help people lose weight; that didn’t pan out. Unfortunately, in obesity, leptin levels are already high and resistance to leptin has developed. When anyone loses weight on any diet, leptin levels drop. Rosedale’s approach is to reduce leptin levels by changing metabolism and reducing leptin resistance, thereby causing weight loss.
Are you leptin resistant? Take this quiz.
He says you are likely to be leptin resistant if you answer yes to any of the questions on his quiz. Do you have trouble losing fat, trouble keeping weight off after dieting, are you constantly hungry, do you crave sweets, do you wake up hungry at night, have a “spare tire” or are apple shaped, feel stressed out, have high triglyceride levels, have high blood pressure, or have osteoporosis? Has this quiz been tested or validated? No. Is this a useful way to learn if you are leptin resistant? No. But it helps sell books.
What is the Rosedale Diet?
It involves two stages. The first stage is designed to teach the metabolism to burn fat, not sugar; for 3 weeks, practically no carbohydrates are allowed. In stage two, more carbohydrates are allowed, but only the healthiest kind with the highest fiber content.
Foods not allowed: dairy, white potatoes, breakfast cereal, rice, bread, peanuts and peanut butters, beans, corn, honey and sugar, all cakes, cookies, ice cream, candies, flavored jellos, and most fruits (pineapple, orange, apple, watermelon, banana, all dried fruit, cantaloupe, honeydew, grapes). Fried foods, all commercially processed oils, all fruit juices, many condiments (mayonnaise, ketchup, etc.), most artificial sweeteners, all soda pop.
Foods allowed in limited quantities (one serving a day or less): carrots, parsnips, peas, fresh or frozen blueberries, raspberries, strawberries, blackberries, lemons, limes, tomatoes. Canola oil only once or twice a week.
Foods allowed daily:
- Protein sources: nuts, seeds, fish, eggs, tofu, poultry, wild meats, protein powder, seafood, veggie burgers, curd/cottage cheese, some cheeses, full fat cream
- Fat sources: Avocados, olives, nuts, butter, unheated cod liver oil, flax oil, fish oil; if you must cook with oil, use olive oil, coconut oil, or ghee
- Carbohydrate sources: lettuce, greens, broccoli, cucumbers, mushrooms, onions, peppers, squash, sprouts, seaweeds, asparagus, some of the smaller beans, black soy beans, Wasa fiber rye crackers (2-3 per day)
- Drinks: teas, coffee substitutes; one cup of real coffee if you can’t give it up entirely
- Alcohol: OK in small amounts
- Condiments: turmeric, cayenne pepper, cumin, basil, oregano, fennel, Masala, ginger, garlic, vinegar, mustard, miso salt, lemon, lime, tamari
- Sweeteners: most are terrible for you, but stevia, xylitol and erythritol are permissible in moderation
- Feel good about yourself
- Eat when you are hungry
- Eat slowly
- Drink lots of water
- Don’t eat for 3 hours before bedtime
- Exercise after the last meal of the day
- Eat the right amount of protein for you (one gram per kilo of ideal body weight minus 10%)
He doesn’t provide any evidence from controlled scientific studies to support any of these recommendations.
He recommends avoiding coffee because it raises blood sugar. Maybe it does, but not enough to worry about: the ADA recommends coffee for diabetics because it is zero-calorie.
He prohibits peanuts and peanut butters because they “contain an element called ‘aflatoxin’, which is a potentially deadly carcinogen.” That’s nonsense. There is no aflatoxin in peanuts unless they are moldy. Aflatoxins are produced by a fungus, Aspergillus, that can sometimes contaminate grains, milk, and peanuts. Peanut products are monitored for aflatoxin in the US. Toxicity is a concern in developing countries, but peanuts sold in the US are not considered a problem.
He claims that targeted nutritional supplements can dramatically enhance the effectiveness of the diet.
His basic supplement plan includes L-arginine, L-carnitine, chromium, CoQ10, lipoic acid, magnesium, potassium, aspartate, a multivitamin without iron, vitamins C and E, and L-glutamine powder. The Rosedale Diet Supplement Plan Plus adds biotin, gymnema sylvestre extract, phosphatidyl serine, and pregnenolone. If you have cardiovascular disease, you should take extra CoQ10 and arginine, plus vinpocetine, vitamin B12, trimethylglycine, and folic acid. If you have diabetes, you should add vanadyl sulfate, extra thiamine, and extra alpha lipoic acid. If you have osteoporosis, you should add vitamin K. If you have arthritis, you should add glucosamine and cetyl myristoleate. He offers some hypothetical rationales based on preliminary cherry-picked studies but provides no evidence from clinical studies that any of these supplements actually improve the health of people on his diet or with those diseases.
Medical tests that can save your life
He recommends that 16 tests be done at your annual physical, with follow-ups at 3, 6, and 12 months to monitor your progress. He says many of these tests can be done as part of the routine CBC that should be done at your annual physical. He explains that CBC stands for complete blood chemistry. It doesn’t; it stands for complete blood count (red cells, white cells, etc.) and is NOT recommended as part of a routine physical. In fact, the routine annual physical itself is no longer recommended.
The tests he recommends, in order of what he considers to be their importance:
- Thyroid function
- Basal body temperature
- C-reactive protein
- Uric acid
- Liver enzymes
None of these tests are recommended on an annual basis by any reputable organization like the USPSTF, and most of them are not recommended at all as routine screening tests in healthy people. He offers no evidence that monitoring these lab values improves clinical outcomes. The only thing that most doctors would check periodically (not annually, and not for certain age groups or low risk groups) is cholesterol, and he considers that the least important thing on the list. In my opinion, ordering these tests is a waste of money, is likely to produce false positives and unnecessary concern, and is likely to do more harm than good.
He warns patients that if you’re on medication for heart disease or diabetes, you should monitor it carefully, because the need for meds will diminish and likely disappear. Maybe. Maybe you would see the same improvement on a different diet. Maybe you will be persuaded to give up medications you really needed.
The science of leptin is new, and we are just beginning to understand its effects. It’s becoming clear that it plays an important role in obesity and many other physiologic processes. But the possible practical clinical applications of this new knowledge are far from clear. Rosedale has convinced himself that he has figured out how to control leptin with diet, but he is relying on hypothesis and speculation, not on evidence from clinical trials. He has seen improvement in his patients; but without a control group, his unsystematic observations are meaningless. He mentions a lot of studies on everything from insulin sensitivity to the effect of protein on aging in fruit flies, but he doesn’t manage to weave them into a coherent evidence-based narrative that would support his claims.
It’s hard to follow Rosedale’s arguments in his book, because he doesn’t cite references for specific claims but only provides an appendix with short lists of references grouped by topic. He repeatedly says things like “I believe” and “I have come to believe,” “I lecture on that topic,” “one day it dawned on me,” “I decided to try,” and “I offer the only alternative diet that works, and works fabulously well.” In his section on supplements, he recommends a total of 24 supplements, but the list of supplement references in the appendix consists of only 5 references that refer to only 5 supplements. And one of those references is a Chinese study of the effects of chromium and fish oil in obese developing rats! It appears that he’s not making a serious effort to provide evidence; it’s as if he expects us to just take his word for most of what he says.
Is anyone really recommending high-carb diets?
Rosedale says all the popular diets today are either high-carb/low-fat or high-protein/low-carb. I think that’s a gross mischaracterization. It may be true that low fat diet recommendations led a lot of people to inadvertently overdo the carbs and contributed to the prevalence of obesity, but current recommendations are for a diet low in calories, not high in carbs. And low carb diets are not necessarily high protein diets. He says a high-carb diet is being prescribed for diabetics. That’s not true: diabetic diets are designed to limit carbohydrate intake. Rosedale puts no limits on calories or fats as long as they are not “killer fats” but good fats that lower leptin levels. The only thing he asks patients to keep track of is their protein intake. I agree that overdoing the protein could lead to harm, but he hasn’t provided the evidence to convince me that he knows how much protein is ideal.
He questions the use of statin drugs. He says they are “not without significant side effects, that they deplete the body of CoQ10 and cause muscle damage”. He goes on to claim that:
Since the heart is a muscle, it is probably getting damaged also, impairing its ability to pump blood and increasing the risk of congestive heart failure. In other words, over time, these drugs can weaken the heart and impair its major function. Sure, in the short run, they may lower cholesterol, but in the long run, they can kill you.
In my opinion, this is irresponsible fear-mongering. Statins have been proven to reduce the rates of cardiovascular mortality and all-cause mortality. They save lives. And he has no evidence that his diet can do any better.
Testimonials and recipes
As with so many fad diet books, this one includes testimonials, recipes, and a month’s worth of suggested menus. That’s all very nice, but it isn’t evidence.
Other opinions about overcoming leptin resistance
Dr. Oz claims that protein and fiber are the keys. He offers a different prescription for overcoming leptin resistance:
- Start your day with peanut butter and oatmeal.
- Take an Irvingia supplement.
- Do not eat for 12 hours between dinner and breakfast the next day.
There are other leptin diets, for instance here.
Rosedale is supremely confident that he knows how to overcome leptin resistance, prolong life, and improve health. He could be right, but I am skeptical. He makes a big deal about showing how leptin levels decrease in his patients, but he has no control group, and we know that leptin levels drop when weight is lost by any means. Leptin doesn’t exist in a vacuum: it interacts with insulin, ghrelin, and a lot of other things. When you change one thing, you may be inadvertently changing a lot of other things that you might not want to change. It’s complicated, and simple one-size-fits-all solutions are seldom the answer to a medical problem. Like any other claim, this one will have to be tested in controlled studies before mainstream medicine can accept it. Even if there is a layer of truth in Rosedale’s hypothesis, the truth is buried under a laundry list of specific recommendations that don’t make sense and are not based on any credible evidence.
Without controlled testing, we don’t have any credible evidence that this diet works as claimed or is safe, but we don’t have any evidence that it doesn’t work or isn’t safe either, so if anyone wanted to try it, I wouldn’t object.
Dr. Joseph Mercola says, “The Rosedale Diet is a must-read for anyone interested in health.” I say neither Mercola nor Rosedale can be recommended to anyone who is interested in science-based medicine.
This article was originally published in the Science-Based Medicine Blog.