Q. When did you first describe the pattern of eating 20 percent/100 percent on alternate days?
A. I filed a patent application on August 12, 2003, called a “priority date,” and a formal application on May 14, 2004, titled “Process for Weight Control and Longevity Extension Through Dietary Management.” My colleagues and I conducted our Asthma Study, which was the first time using a version of the Alternate-Day Diet on humans, in 2004. The results were published in 2006.
Q. Is this a fasting diet?
A. No. It is not. It is about eating significantly less than normal on alternate days, but it is not a fast, although it is certainly possible to eat 0 calories on the restrictive days. The term my patients and I initially came up with to describe the pattern was “up day, down day.” And many online blogs still refer to it as the Johnson Up-Day, Down-Day Diet or simply the Up-Day, Down-Day Diet.
Q. I’ve heard that there are people who don’t approve of this diet. What are their objections?
A. Generally speaking, the people who don’t like the Alternate-Day Diet fall into one of the following categories:
1. People who believe you should not drastically lower calorie intake—a notion with which we agree, if you are doing this on a daily basis, because there is too much loss of lean body mass (muscle) with very low-calorie diets.
2. People who have had anorexia or bulimia and have been taught in therapy that “starving and bingeing” behavior is bad for you. We certainly agree that anyone with an eating disorder should seek professional counseling before starting any new diet, but we disagree with the characterization of the Alternate-Day Diet as starving and bingeing. We advise people to eat to the point of satisfaction (but not beyond) on the up day and to adjust their down-day intake to a level they can tolerate to ensure long-term maintenance of the pattern. Our broad experience is that this pattern creates a gradual increase in control over intake, not the aggravation of eating disorders.
3. People who cannot tolerate the feeling of mild hunger, even intermittently. These people, of course, are usually unsuccessful on any diet.
4. People who claim not to be able to limit themselves to a shake or other simple food even on alternate days. Again, these people are usually unsuccessful on any diet.
5. People who don’t understand or accept the science behind the Alternate-Day Diet even though abundant evidence confirms the health benefits of calorie restriction, as well as the maintenance of metabolic rate and of muscle mass with the alternate-day pattern.
6. People with a bias in favor of other types of diets, such as “low carb.” Despite the evidence that all diets eventually fail, some people believe that since they have lost weight on Atkins, that’s all they need. However, the science of nutrition has shown the importance of a mainly plant-based source of calories.
Q. What is the biggest difference you’ve seen between the time when you created what was originally known as the Johnson Up-Day, Down-Day Diet (aka the Alternate-Day Diet) and today?
A. The degree of acceptance. People throughout the world are now using this diet in one form or another. In the beginning, there was a great deal of skepticism on the part of the public as well as some scientists. However, since the publication of the results of our Asthma Study in 2006, there have been many other papers that confirm our results.
Q. What new information has been discovered recently about the benefits of an alternate-day calorie-restriction diet?
A. Recent studies confirm our earlier findings that you lose much less muscle on the Alternate-Day Diet than when you cut your calories every day. This means that when you lose weight on the Alternate-Day Diet, your physical strength is maintained. You also look better and your muscles are more defined.
One study suggested that eating foods with a higher fat level on your down days may help to reduce hunger. And other findings indicate the Alternate-Day Diet improves factors that are risks for heart disease, such as high blood pressure and cholesterol.
Q. Is it true that the SIRT1 gene, which you refer to as the “skinny gene,” is the primary cause of the health benefits described in the book?
A. There has been some debate about what specific genes are turned on when calories are restricted, but it is now certain that activating SIRT1 is the initiating event. It turns on genes that reduce fat storage and has several other effects that lead to the benefits of disease prevention (including cancer, heart disease, and diabetes), and a healthier metabolism.
Q. I think I have low blood sugar. Is the Alternate-Day Diet safe for me?
A. Hypoglycemia, or low blood sugar, occurs in two forms: reactive and fasting. Reactive hypoglycemia means that two to four hours after eating high-carbohydrate foods, the blood sugar drops too low, producing shakiness, anxiety, sweating, extreme hunger, and palpitations. This is the result of excess insulin release, which drives the blood sugar down. The treatment is to avoid high-glycemic carbohydrates (white flour, rice, potatoes) and sugar by eating low-glycemic foods (vegetables and whole grains) as well as protein- and fat-containing foods, and to eat every three hours. Fasting hypoglycemia is often associated with certain medications, excess alcohol, and with some critical illnesses, and is diagnosed with blood sugar testing after a period of fasting.
If you believe you might be hypoglycemic, you should consult your physician. While symptoms of reactive hypoglycemia can be severe, some people who feel they are experiencing hypoglycemia may not actually have low blood sugar and instead might be experiencing symptoms of “feeling bad,” such as lightheadedness or mental sluggishness. In practice, no one on the Alternate-Day Diet has complained of low blood sugar on the down day when they were using a shake. If you have been diagnosed with hypoglycemia or believe you have hypoglycemia, you should discuss the diet with your physician. You may also wish to buy a glucometer and test your own blood sugar. The OneTouch Ultra Mini costs less than $20, and learning to use it can give you a much better idea of how your blood sugar is responding to what you eat or don’t eat.
Q. I have hypoglycemia. I feel faint and dizzy when I don’t eat because my blood sugar drops, so I can’t do this diet. What should I do?
A. The symptoms of weakness, faintness, and dizziness are rarely caused by hypoglycemia. They are usually due to dehydration and can be alleviated by drinking more fluids.
Q. I am diabetic. Can I follow the Alternate-Day Diet?
A. If you are Type 1 diabetic, it would be too difficult to maintain glycemic control without hypoglycemic episodes and I would advise you not to do the diet.
Type 2 diabetics vary across a broad range in their degree of insulin resistance. Some, especially those controlled by diet, should have no problem. If you are a Type 2 diabetic (90 percent of all diabetics) and are using drugs such as metformin (Glucophage) or rosiglitazone (Avandia) that act by reducing insulin resistance, you should have no low blood sugar problem on the down day. The Alternate-Day Diet reduces insulin resistance, especially if you lose weight, so over time, your medication requirement may be reduced. Before you start this or any diet, however, you should consult the doctor who manages your diabetes.
If you are taking medications that lower blood sugar by increasing insulin release or insulin itself, you would have difficulty controlling your blood sugar, and I would advise you not to do this diet.
Q. Has any other disease been treated with the Alternate-Day Diet?
A. Our Asthma Study showed marked improvement in airway function, and unheard-of reduction (up to 90 percent) in oxidative stress markers, which are the free radicals that cause disease.
Q. Will the diet affect my medications?
A. First, everyone should consult a doctor before starting any diet. In general, however, the Alternate-Day Diet will not affect your medications. If you are using a medication to lower blood sugar (as for diabetes), you will need to closely monitor your blood sugar.
Q. Does this diet have any side effects?
A. I have had no reports of it. My main concern would be experiencing dehydration on the down day because of inadequate fluid intake. Many people are mildly or moderately under-hydrated in normal circumstances, so it is critical to take in the equivalent of 2.5 liters of calorie-free liquids per day. You may not actually feel thirsty when you are exerting yourself and losing water rapidly. And older people may not have a sufficient sense of thirst to avoid dehydration. For these reasons it is important to preempt dehydration by intentionally drinking calorie-free liquids throughout the day. Extreme dehydration occurs mainly in children and old people during very hot weather, but minor dehydration can make you feel tired, weak, and irritable. If your urine is clear or very pale yellow, you are adequately hydrated.
Q. Does the Alternate-Day Diet cause loss of muscle?
A. The loss of any significant amount of weight inevitably causes some loss of lean body mass (muscle). However, I believe that the Alternate-Day Diet preserves lean body mass more than daily weight-loss diets because keeping calories low on the down day activates SIRT1, which turns off the gene PPAR-gamma that is required for fat storage. This means that the Alternate-Day Diet preserves your muscle and you lose mostly fat, and the more SIRT1 is stimulated by keeping down-day calories low, the greater the effect.
This effect was demonstrated in the one-meal-a-day study conducted by Mattson and associates that we discussed here. The people in this study who ate only one meal a day lost 4.6 pounds of fat but only 3.1 pounds of body weight. This means they gained 1.5 pounds of muscle even though they did not alter their physical activity. This is a remarkable result, because normally there would be loss of muscle with any degree of weight loss, and the reduction in body fat by 4.6 pounds is important because, as we have seen, it is the amount of body fat (or lack thereof) that determines health and longevity.
Q. Does the Alternate-Day Diet cause ketosis?
A. In the asthma-diet study, where subjects were consuming less than 20 percent of their daily required calories, they all showed an increase in ketone levels on the down day. Our clinical testing has indicated that if your intake is below 25 percent on the down day there is an increase in urine ketone level. Higher levels of ketones, which are sometimes seen in people whose calories come mainly from fat and protein (i.e., the Atkins Diet), are thought to help suppress appetite and improve stress resistance in the central nervous system. However, if your down day intake is 30 to 35 percent, most people following the Alternate-Day Diet don’t show ketones in the urine.
Q. Isn’t the Alternate-Day Diet a kind of yo-yo dieting, and isn’t that unhealthy?
A. First of all, this diet has nothing at all to do with yo-yo dieting—or weight cycling, as it is called by researchers. “Yo-yo dieting” refers to the repeated loss and regaining of weight over a period of years. The Alternate-Day Diet restricts calories on alternate days in order to achieve permanent weight loss and improved health.
That said, however, it is not clear that the repeated loss and regaining of weight is necessarily harmful to health or if it is more harmful than remaining overweight. Although no one would encourage anyone to purposefully engage in yo-yo dieting, would it be better for people who have lost and gained weight over time to just give up and remain overweight?
Studies of weight cyclers have generally failed to show that they have a higher likelihood of dying or incidence of disease. One study found a lower effectiveness of natural killer cells (monocytes), which defend against viruses and cancer, in women who weight cycled, and the authors speculated that they might, therefore, be less healthy. However, other factors might have been operating; in calorie-restricted animals, the number of lymphocytes declines by one-third but are more effective than normal lymphocytes and the animals show better, not worse health. In healthy, middle-aged individuals, a history of weight cycling does not seem to increase the risk of long-term weight gain in men; however, this relation needs to be studied further in women.
At the moment, there is no definitive answer to the question of whether weight cycling is unhealthy in any way, while the evidence that being overweight causes poorer health is indisputable. It seems highly doubtful, therefore, that overweight people would be better off if they were told they could never be thin and it was hopeless for them to try. As stated by one researcher, “Without more compelling evidence of the risks of weight cycling, warnings overriding safe, effective weight-loss treatments for the obese are unwarranted.”
Finally, there is the question of whether weight cycling makes long-term weight gain more likely. Studies do not indicate that weight gain or fat gain is more likely with weight cycling, nor is there evidence that it gets harder to lose weight with subsequent cycles. In all probability, regaining weight is the consequence of allowing ourselves to eat in an unrestrained and nutritionally undesirable way.
Q. Could the Alternate-Day Diet lead to anorexia or another eating disorder?
A. There have been comments that this diet could cause anorexia, but to date there has been no indication of any relationship between anorexia and the Alternate-Day Diet. I am not aware of anyone who has gone on this diet and subsequently become predisposed to this kind of problem, although there are always people who might abuse the Alternate-Day Diet—or any diet for that matter. In fact, anorexics would not be able to eat a normal amount of food on the up days. And bulimia, to my knowledge, has not been aggravated by the diet.
In 1992, the National Institutes of Health stated, “It is known that the onset of binge behavior occurs only after the experience of dieting.” It also appears that the incidence of eating disorders is on the rise. According to an article in the February 1, 2007, issue of the Journal of Biological Psychiatry, 0.6 percent of the population has anorexia, 1 percent has bulimia, and 2.8 percent has a binge-eating disorder. These disorders are about twice as common among women as men and also correlate with a high incidence of other psychiatric problems: 94 percent of bulimics, 56 percent of anorexics, and 79 percent of binge eaters have another psychiatric diagnosis. One-half have major depression and one-third are substance abusers. Therefore, if you are experiencing emotional problems and think you might have an eating disorder, you should seek professional help before starting any diet program.
Q. If I eat every other day, won’t I develop a vitamin deficiency?
A. No. Vitamin deficiency simply doesn’t happen in just twenty-four hours. As long as you eat sensibly, and supplement as necessary, you won’t have a problem. (You have a much higher chance of being vitamin deficient on a diet of fast food than on the Alternate-Day Diet.)
Q. Should I start on an up day or a down day?
A. If you’re eating normally before you start the diet, technically speaking you’ll have to start on a down day, although you can certainly choose to decide that you’re starting on a normal eating day. One way or another, it doesn’t really matter.
Q. How soon will I experience the positive effects of the Alternate-Day Diet?
A. Both the health effects and weight loss will be felt within the first three days, as they were for the people in our Asthma Study.
Q. How low should I go on the down day?
A. To maximize the response that lowers oxidative stress and inflammation, eating nothing every other day would probably be most effective. Except, of course, that no one can do it!
I originally conceived of the Alternate-Day Diet as eating 20 percent of normal on the down day because I estimated that this amount would be tolerable in terms of hunger control while simultaneously activating the calorie-restriction mechanism. It’s proved to be acceptable to a large percentage of motivated dieters. Some individuals, however, find 20 percent to be too low and prefer 30 to 35 percent and have seen both weight loss and good health results at that level. I myself generally adhere to a 50 percent down-day level alternating with roughly 100 percent up days interspersed with days of 25 to 35 percent.
The effectiveness of any diet is completely contingent on the ability of the dieter to comply over time. Therefore, you need to determine the level you can tolerate for the long term.
Q. I’ve heard that the most successful dieters are those who eat a good breakfast. Is that true, and how can I eat a good breakfast on my down days?
A. There are numerous studies purporting to show better cognitive function and decreased tendency to overeat in people who eat breakfast. Records from the National Weight Control Registry, which tracks successful dieters, indicate that 78 percent of these people eat breakfast. The implied reasons are that skipping breakfast will just set you up to eat more when you finally get so hungry that you gorge, and also that eating breakfast jump-starts your metabolism to burn more calories. There is, however, no good scientific basis for either of these claims. Assumedly all those successful dieters became overweight by eating (at least) three meals a day. If you want to eat a good breakfast on your up days, please do!
Q. What’s the difference between having a shake and eating a five-hundred-calorie lunch, as some other diets recommend?
A. Either one will work. The midday lunch is based on the notion that it helps you to reduce hunger and stay alert. However, most people like to have some calories in the morning and a small amount throughout the day, using either the shake or very low-calorie foods.
Q. Don’t you need to eat frequently to rev up your metabolism so that you burn more calories in order to lose weight?
A. The answer to that question is a definitive no. This is one of the common myths about metabolism, but without any basis in physiology. While it is true that the process of digestion does expend some energy and, therefore, increases your metabolic rate, in order to have a net negative-calorie effect (and thus lose weight), the food you were eating would have to have fewer calories than the calories burned in digesting it. This might apply if you were eating sawdust, which is indigestible and would require some energy expenditure to push through the GI tract, but it would certainly not apply to eating any normal food. All normal food has more calories than what your body requires to digest it—that’s why it’s called food.
Q. What do I do if I blow it on a down day?
A. First off, realize that you have begun! You have made a conscious decision to follow the Alternate-Day Diet, and you are doing your best (which is all any of us can do). Second, no one can do this or any diet perfectly. Life gets in the way. Third, you can start over tomorrow. You will have some great down days and others when you will blow it. When you do, you have two choices: turn the down day into an up day or make the down day an in-between day. The worst thing to do is to succumb to all-or-nothing thinking that you may as well pig out since you’ve already blown it.
Q. What happens if I miss a down day?
A. SIRT1 is turned on by the low-calorie intake of the down day, remains active for more than twenty-four hours after the end of that day, and is probably present in decreasing concentration for several more days. The repetition of the down days increases SIRT1 protein levels to a maximum after approximately three weeks. Therefore, if you miss a down day after following the diet for some time you would experience a decline in SIRT1 protein levels but still have much of the desirable anti-inflammatory activity. If, on the other hand, you had only done one or two down days, you would not have achieved maximum stimulation of the SIRT1 response and would lose those benefits more quickly. If you stop the diet completely, it appears to take twenty-one days to lose most of the beneficial effects.
Q. I don’t want to do down days on the weekend. Can I do them on Monday, Wednesday, and Friday?
A. Many people find it easiest to do Monday, Wednesday, and Friday down days and make either or both Saturday and Sunday up days. This works well and clearly maintains activation of the anti-inflammatory process. However, most people eat more on weekends, probably because they are not distracted by work and engage in more social activity. So, if you are trying to lose weight on the Alternate-Day Diet, you should exercise caution and keep an up-to-the-minute food log to remain conscious of what you are eating. As soon as you eat something, write it down.
Another strategy would be to make Sunday an “in-between” day, meaning that you still restrict to some extent but eat more than you would on a regular down day. Some alternate-day dieters have found that this works for them while others have found that calculating in-between day calories just adds to their stress and, therefore, becomes counterproductive. Again, as I’ve said before, it’s a matter of knowing yourself and what works for you.
Q. How does the Alternate-Day Diet compare to the 5/2 diet?
A. The 5/2 diet is simply restricting calories two days a week rather than every other day. This may be easier for some people to do, and there is evidence that it would result in better health than doing nothing at all. Restricting calories even one day a month has been shown to improve health. But the Alternate-Day Diet provides the best results.
Q. Can I do two down days in a row?
A. You can, but it’s very unpleasant, and you’ll also be slowing your metabolic rate, which will counteract the benefits of the alternate-day pattern.
Q. How much should I eat on the up day?
A. To answer that question, it is important to understand the psychology of the Alternate-Day Diet, the point of which is to reduce stress and diet fatigue and increase freedom from the anxiety of restricting every day so that you are more likely to adhere to the diet over time.
Oddly, based on the Calorie Calculator, some dieters seem to believe that there is a number of calories they are required to eat on the up days. However, the sole purpose of using the Calorie Calculator is to estimate the number of calories to eat on your down days. You absolutely do not have to consume all the calories estimated for your up days. There is no specific calorie requirement for the up day.
The most important principle of the Alternate-Day Diet is to keep your down-day calories as low as practical while maintaining the up-day, down-day pattern over the long term.
Q. What about carbs?
A. This diet is strictly about calories, but many people find that minimizing “white foods,” on both the up and down days, but especially on the up days, helps them lose weight. Since the down days are all about consuming low-calorie foods, this would naturally preclude sugary or starchy carbs. It’s the calorie restriction that activates SIRT1—no matter where those calories come from. For more information on carbs and this diet, check out lowcarbfriends.com/bbs/juddd.
Q. What about going “low carb” on the up day?
A. We have covered the principles of good nutrition in Chapter 7, which you should keep in mind if you intend to follow the Alternate-Day Diet indefinitely. The answer to this question centers on understanding that if you are overweight, you are always going to have to control your eating. The only logical long-term solution—given the huge potential benefits—appears to be the practice of restraint every other day.
Following a plan of the traditional Atkins type, which includes large quantities of saturated fat, is not recommended. If you follow a plan with healthier sources of protein, such as chicken, fish, and low-fat dairy, you may find it more satiating. The bottom line is that if you are going to benefit from the modern science of nutrition, it is necessary to consume whole grains and non-starchy vegetables—that is, healthy carbohydrates—in sufficient quantities.
Some people have found it easier during the active weight-loss phase to follow a low-glycemic, high (healthy) protein diet on the up day, and then shift to a more vegetable-based diet once they reach their goal weight.
Q. Do I need to exercise?
A. Exercise is definitely essential for good health, but exercise alone will not cause significant weight loss. It is necessary to keep your down-day calorie intake to no more than 25 percent of normal to get the maximum benefit of the diet. This is important because many people use exercise as a handy excuse to eat more.
Thirty minutes of aerobic exercise daily and resistance training three times a week is a program most people are able to maintain. Those who do significantly more aerobic exercise can increase their down-day intake, but doing that is a slippery slope, because most people underestimate the number of calories they are consuming.
Q. How do I fit this plan into my family’s lifestyle?
A. You can cook for your family in advance on your up days and refrigerate or freeze what you’ve cooked until needed. To avoid succumbing to hunger on your down days, try going for a walk while your family is eating, or join them at the table with a large bowl of greens dressed with vinegar and a teaspoonful of oil.
Q. Will I gain weight if I go off the diet?
A. Most people who lose weight on any diet regain it within a year or two. The Alternate-Day Diet appears to have a lower level of recidivism; however, the fact is that 90 percent of the population will gain weight over time in our cheap and available food environment. People who are successful with the Alternate-Day Diet make it a lifestyle, and if life prevents them from being consistent for some period of time, it’s easy to restart.
Q. How much is this diet going to cost me?
A. Many diets require the purchase of specific, potentially expensive foods. This diet does not. The only additional cost would be the shakes I recommend for the first two weeks of the diet, but even those cost less than the food you would normally be buying to eat on your down days.