Visit Your Local PBS Station PBS Home PBS Home Programs A-Z TV Schedules Watch Video Donate Shop PBS Search PBS
SAF Archives  search ask the scientists in the classroom cool science
scientists from previous shows
cool careers in science
ask the scientists
PREVIOUS SCIENTISTS

Photo of Roy Walford Roy Walford as seen on Never Say Die: Eat Less - Live Longer

Click on Roy's photo to read a brief bio.



q Can you please give us the recipe for the wonderful salad you made on Eat Less - Live Longer? (Question asked by many viewers)

A Click here for the recipe. For more nutritious, low-calorie recipes, please visit Dr. Walford’s kitchen.


q Have you written a book that explains the principles of your diet, provides recipes or analyzes one's diet for nutrition? (Question asked by many viewers)

A Yes, the book's title is "The Anti-Aging Plan", published by Four Walls Eight Windows press, New York.


q You say a calorie-restricted diet helps you live longer. But how specifically does the lack of calories help your body? I thought that calories give you energy…isn't that something you need? (Question from Kasia, 9th grade student)

A A low-calorie nutrient-dense diet induces a rearrangement of metabolism towards an increased efficiency of the use of calories, with reduced oxidative damage, increase in DNA repair mechanisms, and other age-retarding effects. All this is proven in rodent studies; and evidence to date suggests that primates, including humans, will react the same way.


q I'm very interested in your idea of maintaining good health. You said to dothis you need a diet that is low in calories and has high nutritional value. If someone my age, 16 years old, were to start a diet, like this, what age would he or she be expected to live to? And would this diet have any damaging effects on this person physically? (Question from Milla, student at St. Josephs Academy)

A If animals are put on such a diet when very young, they live a great deal longer and are extra-healthy, but they never achieve full growth. So you wouldn't want to start it until you are fully grown. But abstracting from animal data, one would expect humans on a suitably restricted diet to be on a survival curve terminating at about 160 years, instead of the present one which crosses zero at about 110 years. Of course when you as an individual fall off that 160-year curve cannot be foretold, just as one cannot know when he or she will fall off the present 110-year curve. But barring accident, you should live a great deal longer than you otherwise would have, and appear much younger than your actual birthday age.


q What are your thoughts on the currently popular high protein-low carbohydrate diets? I've read the books: The New Dr. Atkins Diet Revolution, Sugar Busters and Sugar Blues....and I would like to know how you think following these plans will affect general health and overall well-being, as well as weight loss and possible extension of life? (Question from Tevana)

A If they are low-calorie and nutrient-dense, they should retard aging; however, I do not favor these diets. They have not been well researched at all. They may lead to quick weight loss, and so are popular, but the effects of their long-term usage are unknown.


q I am a school teacher and we have studied the Biosphere II experiment. What do you think is the greatest lesson from this experiment? Would you ever do such a long-term experiment again? Thank you for this fascinating lesson in our ever-seeking quest for knowledge. (Question from Janet)

A The major overall "lesson" or result is that a biosphere can be constructed, and, with some human input in the way of "adaptive management", will survive and be self-regulating and self-sustaining. Biosphere 2 did not quite achieve all these ends, but came close enough that we know it can be done. On Mars and elsewhere, when we get there, we will be living in biospheres that we construct. Biosphere 2 was simply the first one, the prototype. No, I wouldn't do it again in Arizona; but I would on Mars.


q What computer program were you using to determine the nutritional value of the meals prepared on the show? Is this program commercially available (Question asked by many viewers)

A The computer program is called "The Interactive Diet Planner" and is available through The Longbrook Company. Details may be found on my web site, www.walford.com. This is the program I devised for use inside Biosphere 2. The present version has been extensively up-dated and improved.


q You advocate being 10-20% under "set-point" weight. Can you explain how you can determine what your "set-point" is? (Question asked by many viewers)

A Your "set-point" is what you weigh or would weigh if you simply eat normally, whatever "normally" for you happens to be. Also, it is generally what you weighed when you were around 25 years old. For example, I weighed about 150 pounds when I was in that age-group, and had to watch my food intake and train "down" a few pounds to make my weight for the University of Chicago wrestling team. My "set-point" is therefore 150 pounds.


q How do people feel on calorie-restricted diets? You seem to be saying that the health benefits do not begin in old age but manifest themselves right away -- how does this diet affect how people feel day to day? Do they feel like starvation victims? Do they think about food all the time? Do they have increased energy? Do they sleep well? Basically, I am asking: Your program sounds like torture. Is that what it feels like? And please do be completely honest -- I will find it hard to believe that this is an easy program to get on and follow, with no difficult things about it. (Question from Lydia)

A How people feel depends on (a) how much restriction they undertake, (b) the characteristics of the individual person, and (c) the "quality" of the diet they were on compared to the "quality" of the restricted diet.
  • (a) The degree of life span extension, and other benefits, is proportional to the degree of restriction. Even 10% restriction will lead to a mild increase in life span and other benefits. That's not at all difficult. Maximal life extension would be achieved at about 50% restriction, and would be quite difficult to keep up (and should not be undertaken unless under close medical supervision). Over 50% restriction will lead to caloric starvation. So you should settle on whatever is comfortable for you. 30% is better than 20% is better than 10% but don't go overboard, and you should loose weight slowly. It's not a crash diet.

  • (b) On an individual basis. some people can be on a restricted regime and be comfortable, some have more trouble. Most can find a level of restriction that can be sustained. In proportion to this level, most people need less sleep and have increased energy. Health benefits manifest themselves fairly soon -- within 4 to 6 months. You get colds less frequently, for example. Blood pressure declines somewhat. Your sense of "well-being" increases. And you look better.

  • (c) Even without restriction, a nutrient-dense diet of the type spelled out in "The Anti-Aging Plan" is health-enhancing compared to the usual American diet.
Wrapping up (a), (b), and (c) I can summarize by saying that it's not all that difficult to do if you are motivated, i.e., if you really and truly want to live long enough to see how the world is doing in the year 2100, and to still be playing an active part in that world; or if you have a genetic tendency for a disease such as cancer (of the breast, colon, etc.), hypertension, auto-immune disease etc., and want to decrease your chance of getting it; if for professional reasons (actor, fashion model, athlete) it's important to remain youthful as long as possible.


q Have any studies been done on the effect of calorie restriction on athletic performance? Because I participate in so many sports, I'm concerned that restricting my calorie intake will reduce athletic performance. Will the weight lost due to the reduced calorie intake reduce muscle mass? Will there be a loss in energy? (Question asked by many viewers)

A No in-depth studies have been made of this question in humans, so only anecdotal evidence is available and not much of that. It would in any case depend on the sport and on the degree of calorie restriction. People who run claim they do better on a low-calorie, nutrient-dense diet. Thus, stamina may be improved but physical strength be less. But if your "normal" weight is 150 and you restrict yourself down to 125, you will be weaker than you were at 150 but strong for a 125 pounder. For a mouse, 36 months is old age. Now if mice are restricted beginning at 3 months, and then tested when they are 36 months of age, they perform both in tests of physical agility and of mental ability as well as normally fed 6-month old mice. By this token, if you restrict yourself from age 25 and test yourself at 50, you will far far far out-perform any other "normal" 50-year old person. So the answer to your question depends on just what you intend by the question. Try it and see. If you don't like what you find, return to your old ways.


q Is there any evidence that eating a calorie-restricted, highly nutritious diet actually reverses aging to some extent, or does it only retard the aging process from the time that you begin the diet? And is there any evidence this diet can reverse diseases, such as heart disease or diabetes? (Question asked by several viewers)

A As far as reversing aging, the answser is both yes and no. Blood pressure and blood sugar, for example, tend to increase with age, and the diet will return those and many other values to those of a younger age. Same for the immune response. So in a limited sense, that's "reversal" of aging. But wrinkles, graying of hair, and other parameters will not be reversed, only slowed down in their advance. So I am very hesitant to claim anything like "reversal."

While there is over 50 years of animal research, calorie restriction has not as yet been specifically tested for treatment of heart disease and diabetes in humans, but judging by what it does for the "risk factors" of those diseases, it should have strong therapeutic effects. In my view, nobody should be going for bypass cardiac surgery who has not FIRST been offered nutritional treatment of their condition. Then, those who can't or won't do it -- they go to the operating room. The others improve without surgery.



q We were just wondering if you ever get cravings for foods that aren’t on your diet. (Question asked by several viewers)

A Well, what foods? If you mean cream cheese, ice cream, and pecan pie, for examples, the answer is no. Once you are accustomed to a high quality diet, any hunger is directed towards good foods, not bad foods. People who crave crave crave some particular food that's not very healthy are generally not on good diets to begin with. It's fast-foodies who crave French fries and rich cakes, not people like me.


q If I now consume an average diet and I decided to converted to a low calorie-highly nutritious diet, then about how long would it take for me to benefit from that diet. In other words how long would it take for my body to adjust to this new diet and for me to begin to live longer? (Question from Jeff)

A Depends on the degree of calorie restriction. The crew of Biosphere 2 showed significant benefits as measured by risk and other factors by 4 months. So at least by 6 to 8 months, if you are doing it right, you should have significant positive changes in blood pressure, blood sugar, and blood lipids, and other items.




 

Scientific American Frontiers
Fall 1990 to Spring 2000
Sponsored by GTE Corporation,
now a part of Verizon Communications Inc.