practice applicationsBEYOND THE HEADLINES

What You Should Know about Calorie Restriction

esearchers at Washington Uni- from animal studies—and now from WHY IT MAY WORK versity School of Medicine in this latest human study—which show For CR to produce its anti-aging ef- RSt Louis, MO, reported in April that an animal’s lifespan can be in- fects, it doesn’t really seem to matter 2004 that people who followed a re- creased, and its health can benefit, by what kind of calories are restricted. stricted-calorie (between 1,100 restricting the number of calories it The anti-aging effects associated with and 1,950 calories a day) experienced consumes so long as its intake of es- CR are due to the restriction of the a dramatic drop in cholesterol levels sential nutrients is maintained.” sheer number of calories, not in a re- and blood pressure, and the subjects As opposed to weight-loss plans, duction of fat, , or any were at lower risk of heart disease there is no set of rules dictating how other particular food group. In fact, and , among other diseases. CR should be followed. There are as Charles V. Mobbs, PhD, associate News outlets all over the country re- many ways to practice CR as there professor of neurobiology and geriat- ported this new eating plan while at are practitioners. Some cut calories rics at Mt Sinai School of Medicine in the same time asking how anybody New York, NY, explains that “the re- could follow this diet. across the board, some skip a , some fast. They also differ in how sponses to caloric restriction can Calorie restriction (CR), however, is largely be understood as helping to many calories they restrict. Because not new. Researchers have known for preserve nutritional resources. Thus, there “appears to be a linear correla- some time that calorie restriction in growth and reproduction are reduced, laboratory animals increases their pos- tion between the degree of restriction since these functions use precious nu- sible lifespan. There is even a society and the lifespan and health benefits tritional resources.” He continues, for people who follow such an eating gained,” May says, there are “CR “The neuroendocrine system very plan, the Calorie Restriction Society practitioners who restrict, for in- closely monitors fuel availability to (www.calorierestriction.org). The Wash- stance, only 10% from the RDA [Rec- make sure we don’t run out of fuel on ington University study is merely the ommended Daily Allowance] of ap- the one hand, or have so much fuel in first involving humans as voluntary proximately 2,000 calories, and who the form of fat that we lose our mobil- subjects, who were members of the Cal- hope to gain a 10% increase in life- ity.” However, Mobbs adds, “We don’t orie Restriction Society. The only pre- span and health improvements.” Oth- really understand why insulin sensi- vious human study was accidental. The ers restrict as much as 20% or 50% tivity is so exquisitely sensitive to ca- participants of Biosphere, in 1991, from the RDA to gain a proportional loric restriction.” found themselves unintentional sub- increase in lifespan and health. jects when their food supply ran short. However, judging by several markers, CAN PEOPLE STICK WITH IT? “Any time a diet is so restricted [as their health seemed to improve (1). CR VS ANOREXIA CR], you have to look at it as thera- May and other CR practitioners ac- peutic,” as opposed to simply a life- CR VS knowledge that CR may attract an- style change, says Molly Gee, MEd, To those unfamiliar with CR, it may orexics or even justify anorexia to RD, chair of ADA’s Weight Manage- appear that this is no different than some people. The difference between ment dietetics practice group and a dieting. Liza May, MS, a member of CR and anorexia is the same as that researcher and lead interventionist at the Calorie Restriction Society and a between CR and weight-loss plans: the Behavior Medical Research Cen- clinical nutritionist in Gambrills, the focus of CR is health and longev- ter at Baylor College of Medicine, MD, whose area of expertise is the ity, the focus of anorexia is weight Houston, TX. “It’s not the way people psychology of eating (ie, food addic- and appearance. Typically, those who want to live. Food is so ingrained in tions, psychology in weight-loss diet- our culture,” she continues. “In addi- suffer from anorexia think in terms of ing, fringe/specialized diets, cultural tion to building and repairing the black-and-white, such that if they issue, and eating disorders), says that body, food plays so many roles in life, the difference is that CR is not about “cheat,” it means that they are “bad.” for example, in family and business.” weight. “Rather, the focus is on calo- In CR, cheating is allowed, even en- She says that while diet plays an im- ries consumed,” she says. “The rea- couraged. There is more a sense of portant part of peoples’ lives, “you soning behind the diet is the findings self-love present in CR as opposed to want a diet you can live with, not a the self-hate present in those who suf- diet you have to retrofit your life fer from anorexia. Because anorexics around.” This article was written by Jim are only focused on appearance in- Mobbs agrees: “Very few people can McCaffree, a freelance writer in stead of health, they may restrict cal- stay on such a diet in the long term: it Los Angeles, CA. ories, but their diet may be unhealth- is very annoying to be hungry, doi: 10.1016/j.jada.2004.08.023 ful (2). cranky, and cold all the time.” In

1524 Journal of the AMERICAN DIETETIC ASSOCIATION © 2004 by the American Dietetic Association For more information circle 75 on Reader Service Card or enter www.info.ims.ca/3281-75 BEYOND THE HEADLINES fact, he says: “I am completely op- lieves that “the basic mechanism by 2. May L. Calorie restriction or an- posed to people trying to follow a true which caloric restriction increases orexia nervosa? Available at: caloric restriction diet. Certainly for lifespan is intact in humans—it ap- http://calorierestriction.org/book/ most people a degree of caloric restric- pears to be almost universally con- view/251. Accessed June 30, tion, to get into the BMI [body mass served in animals—but is not 2004. index] range of 20 or so, would be very activated in humans by caloric re- healthy, but to get below that by dint striction.” However, he adds, “if the of willpower-induced near anorexia is mechanism is intact, and if we can asking for trouble.” understand the mechanism, we May admits that CR is not for ev- should be able to activate it pharma- eryone. She says, however, that “the cologically. This would be a much bet- idea that CR, done properly, should ter way to go than actual caloric re- be difficult, austere, with deprivation, striction.” For him, that is the goal of abstinence, and ‘virtuous’ suffering studying the mechanisms of caloric . . . is erroneous. This is a diet people restriction. can stick with.” She adds that if some- one is already following a proper diet, WHAT TO TELL YOUR CLIENTS all it takes to accomplish is a 5% or While people may not seek out dietet- 10% restriction in calories is cutting ics professionals to inquire about CR, breads or cakes “just a little,” or lim- the increased media coverage may iting sugary, high-calorie candies, change that. May says that if a person desserts, or sodas. As for the psycho- wants to embark on a CR diet, she logical challenges of sticking with the starts the client out gradually. She plan, “CR is not, and should not be, a advises dietetics professionals to miserable, difficult challenge. If so, it know their clients well enough to is too severe, and should be cut back know their issues, psychological chal- to manageable levels that can be lenges, and motivations. Because CR maintained long term. The social, is a diet that does not specify what psychological, and lifestyle challenges people should eat, but simply how are not difficult if the diet is em- much, she says a CR diet needs to be barked upon gradually and the chal- tailored to the needs of each individ- lenges managed little by little, as they ual. In fact, she says, CR might work arise, and when the diet is not notice- for some people, but it might not work ably different from ordinary eating.” at all for others. Plus, through the Calorie Restriction Gee, however, cannot recommend Society, there is a network of people this diet. She says that if a client asks willing to provide support. about it, she says to “give your honest Gee cautions, though, that “this is opinion, then tell them the good news not a plan that people should Google that there is already a lot they can do and say, ‘this is for me.’ You’d have to to increase lifespan: eating a bal- be extremely motivated and obsessive anced diet, having a good weight for to stay on this plan.” One of her con- body size, and following the USDA cerns is that physical activity may not dietary guidelines.” However, she be possible on CR: “If you’re in re- says that if someone is determined to serve mode, you won’t be able to get try CR, she says her mantra is “First the 1 hour of exercise the National do no harm,” which means to have the Institute of Health recommends.” Gee client check with a physician to make also says that people who restrict sure they have no deficiencies in min- their caloric intake as much as CR erals or in their immune system. calls for, may have depleted their re- Finally, Gee says people should re- serves, and their immune system may member that “there is no magic food not be able to fight off sickness, a par- or gene to increase .” ticular concern in winter and flu sea- son. In fact, they may need to eat more in case of sickness. References Mobbs doubts that CR will increase 1. Stein R. Low-calorie diet may human lifespan. “There have been so- lengthen life. Washington Post. cieties, for example, Buddhist monks, April 20, 2004. Available at: whose members were essentially ca- http://www.washingtonpost.com/ lorically restricted throughout life, ac2/wp-dyn?pagenameϭarticle& but there is no evidence any human contentIdϭA25564-2004Apr19& ever lived beyond the maximum life- notFoundϭtrue. Accessed July span of about 125 years.” Mobbs be- 14, 2004.

1526 October 2004 Volume 104 Number 10