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Anti-Aging Diet

Cengage Learning 2012-12-31
Photo © Food and Drink-Rex Features Photo

Definition

The anti-aging diet, also called the calorie-restriction diet, is one that restricts calorie intake by 30%–50% of the normal or recommended intake with the goal of increasing human lifespan by at least 30%. When combined with a healthy lifestyle, people on the diet tend to have improved health, providing they consume adequate vitamins, minerals, and other essential nutrients.

Origins

The idea that a calorie-restrictive diet can significantly increase lifespan has been around since the 1930s. In 1935, Cornell University food researchers Clive McCay and Leonard Maynard published their first in a series of studies in which laboratory rats were fed a diet that had one-third fewer calories than a control group of rats. The lower-calorie diet still contained adequate amounts of vitamins, minerals, protein, and other essential nutrients. This calorie-restrictive diet provided much less energy than researchers had previously thought rats needed to maintain growth and normal activities. The rats on the lower-calorie diet lived 30%–40% longer than the rats on a normal calorie diet. Since then, more than 2,000 studies have been carried out, mostly on animals, investigating the connection between calorie restriction and increased longevity.

A reduced-calorie diet was taken a step further by University of California, Los Angeles, pathologist Roy Walford, who studied the biology of aging. In 1986, he published The 120-Year Diet and a follow-up book in 2000, Beyond the 120-Year Diet, in which he argued that human longevity can be significantly increased by adhering to a strict diet that contains all the nutrients needed by humans, but with about one-third the calories. In 1994, he co-authored The Anti-Aging Plan: Strategies and Recipes for Extending Your Healthy Years. His anti-aging plan was based on his own research and that of other scientists, including his study of diet and aging conducted as chief physician of the Biosphere 2 project in Arizona in the early 1990s. Walford was one of eight people sealed in Biosphere 2 from 1991 to 1993 in an attempt to prove that an artificial closed ecological system could sustain human life. He also co-founded Calorie Restriction Society International in 1994. Walford died in 2004 at the age of 79 from complications of amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig's disease (US) and motor neurone disease (UK).

Description

Anti-aging diets are regimes that reduce the number of calories consumed by 30%–50%, while allowing the necessary amounts of vitamins, minerals, and other nutrients the body needs to sustain itself and grow. Calorie restriction has been shown to increase the lifespan of various animals, including rats, fish, fruit flies, dogs, and monkeys, by 30%–50%. A few human studies have been done, but evidence of its impact on humans is very limited compared to results available from the animal studies. The completed studies suggest that calorie restriction may increase the maximum human lifespan by about 30%. The problem preventing scientists from offering substantive proof that humans can greatly increase their lifespan by restricting calories is that the current maximum human lifespan is 110–120 years and full compliance with the diet is difficult. A 30% increase would extend the human lifespan to 143–156 years. This is an exceptionally long time for a scientific study and requires involvement of several generations of scientists. Only several hundred people have ever been documented to live past age 110. The oldest person with confirmed documentation was Jeanne Louise Calmet (1875–1997) of France, who lived 122 years and 164 days.

Since 1980, dozens of books have been published offering specific calorie-reduction diets aimed at increasing lifespan. The most popular diets include the Okinawa Diet, Anti-Inflammatory Diet, Longevity Diet, Blood Type Diet, Anti-Aging Plan, and the 120-Year Diet. In the 2010s, other anti-aging diets emerged that were not entirely based on very low calorie intake. These include the Origin Diet (unprocessed food only, wild game), the RealAge diet (fruits, vegetables, whole grains, soy), the Eat Right, Live Longer diet (organic vegetarian), and the Age-Free Zone Diet (a high-protein, low-carbohydrate, calorie-restricted version of the Zone Diet).

Despite calorie restriction, maintaining a balanced intake of nutrients is essential for achieving any anti-aging effects. People who experience starvation or famine receive no longevity benefits since their low calorie intake contains inadequate nutrition. The calorie-restrictive diet is believed to most benefit people who start in their mid-20s, with the beneficial effects decreasing proportionately with the age one begins the diet.

Although there are variations among anti-aging diets, most reduced-calorie diets recommend a core set of foods. These include vegetables, fruits, fish, soy, low-fat or non-fat dairy products, nuts, avocados, and olive oil. The primary beverages recommended are water and green or black tea.

Guidelines on calorie reduction vary from diet to diet, ranging from a 10% reduction to a 50% reduction of normal intake. Roy L. Walford (1924–2004), author of several books on anti-aging diets, says a reasonable goal is to achieve a 10%–25% reduction in a person's normal weight based on age, height, and body frame. The Anti-Aging Plan diet recommends men of normal weight lose up to 18% of their weight in the first six months of the diet. For a six-foot male weighing 175 lb. (79.3 kg), that means a loss of about 31 lb. ( (14 kg). For a small-framed woman who is five-foot, six-inches tall and weighs 120 lb. (54.4 kg), the plan recommends losing 10% of her weight in the first six months, a loss of 12 lb. (5.4 kg).

Walford's Anti-Aging Plan is a diet based on decades of animal experimentation. It consists of computer-generated food combinations and meal menus containing the United States Department of Agriculture's dietary reference intakes (formerly called recommended daily allowances) of vitamins and other essential nutrients using foods low in calories. On the diet, the maximum number of calories allowed is 1,800 per day. There are two methods for starting the diet: rapid orientation and gradual orientation.

The rapid orientation method allows people to eat low-calorie meals rich in nutrients. This is a radical change for most people and requires a good deal of willpower. All foods low in nutrients are eliminated from the diet. The nutritional value and calories in foods and meals is determined by a software program available for purchase from Calorie Restriction Society International.

The gradual orientation method allows people to adopt the diet over time. The first week, people eat a high-nutrient meal on one day. This increases by one meal a week until participants are eating one meal high in nutrients every day at the end of seven weeks. Other meals during the day consist of low-calorie, healthy foods, but there is no limit on the amount a person can eat. After two months, participants switch to eating low-calorie, high-nutrition foods for all meals. Dieters are advised to view this diet as a lifestyle change rather than a quick weight-loss program.

A sample one-day, low-calorie, high-nutrition menu developed by Walford is:

  • Breakfast: One cup of orange juice, one poached egg, one slice of mixed whole-grain bread, and one cup of brewed coffee or tea.
  • Lunch: One-half cup of low-fat cottage cheese mixed with one-half cup of non-fat yogurt and one tablespoon of toasted wheat germ, an apple, and one whole wheat English muffin.
  • Dinner: Three ounces of roasted chicken breast without the skin, a baked potato, and one cup of steamed spinach.
  • Snack: Five dates, an oat bran muffin, and one cup of low-fat milk.

The three meals and snack contain 1,472 calories, 92 g protein, 24 g fat, 234 g carbohydrates, 27 g fiber, and 310 g cholesterol.

Function

The goal of the anti-aging diet is to slow the aging process, thereby extending the human lifespan. Even though it is not a weight loss diet, people taking in significantly fewer calories than what is considered normal by registered dietitians are likely to lose weight. Exercise is not part of calorie reduction diets. Researchers suggest people gradually transition to a reduced calorie diet over one or two years since a sudden calorie reduction can be unhealthy and even shorten the lifespan.

There is no clear answer as to why severely reducing calorie intake results in a longer and healthier life. Researchers have various explanations, and many suggest it may be due to a combination of factors. One theory is that calorie restriction protects DNA from damage, increases the enzyme repair of damaged DNA, and reduces the potential for genes to be altered to become cancerous. Other calorie reduction (CR) theories suggest that:

  • CR helps reduce the production of free radicals (unstable molecules that attack healthy, stable molecules). Damage caused by free radicals increases as people age.
  • CR delays the age-related decline of the human immune system and improved immune function may slow aging.
  • CR slows metabolism (the body's use of energy). Some scientists propose that the higher a person's metabolism, the faster they age.

Benefits

The primary benefits of the anti-aging diet are improved health and prevention or forestalling of diseases such as coronary artery disease, cancer, stroke, diabetes, osteoporosis, Alzheimer's, and Parkinson's disease. Studies show that most physiologic functions and mental abilities of animals on reduced calorie diets correspond to those of much younger animals. The diet also has demonstrated extension of the maximum lifespan for many of the life forms on which it has been tested.

Precautions

A reduced-calorie diet is not recommended for people under the age of 21 as it may impair physical growth. This impairment has been seen in research on young laboratory animals. In humans, mental development and physical changes to the brain occur in teenagers and people in their early 20s that may be negatively affected by a low-calorie diet.

Other individuals advised against starting a calorie-restricted diet include women who plan to become pregnant, women who are pregnant, and those who are breastfeeding. A low body mass index (BMI), which occurs with a low-calorie diet, is a risk factor in pregnancy and can result in dysfunctional ovaries and infertility. A low BMI increases the risk of premature birth and low birth weights in newborns. People with existing medical conditions or diseases should be especially cautious and consult with their physician before starting.

It is imperative that participants ensure that they continue to consume adequate levels of essential nutrients. Nutritional supplements and other forms of nutritional help are likely to be needed.

Risks

The anti-aging diet is very restrictive, and dieters need to adhere strictly to diet plans to ensure that they are receiving required amounts of key nutrients. A wide range of risks, related to physical, mental, social, and lifestyle issues, is associated with such a low-calorie diet. They include:

  • hunger, food cravings, and obsession with food
  • loss of strength or stamina and loss of muscle mass, which can affect physical activities, such as sports
  • decreased levels of testosterone, which can be compensated with testosterone supplementation
  • rapid weight loss (more than two pounds a week), which can negatively impact health
  • slower wound healing
  • reduced bone mass, which increases the risk of fracture
  • increased sensitivity to cold
  • reduced energy reserves and fatigue
  • menstrual irregularity
  • headaches
  • drastic appearance changes from loss of fat and muscle, causing people to look thin or anorexic

Social issues can arise over family meals, since not all family members may be on a reduced-calorie diet. Conflict related to the types of food served, the amount of food served, the number of meals in a day, and fasting may develop. Other social issues involve eating in restaurants, workplace food, parties, and holidays. The long-term psychological effects of a reduced-calorie diet are unknown. However, since a low-calorie diet represents a major change in a person's life, psychological problems can be expected, including, in some cases, anorexia nervosa, binge eating, and obsessive thoughts about food and eating.

Research and general acceptance

Animal studies generally support the idea that a calorie-restrictive diet with adequate intake of essential nutrients increases lifespan. Few studies have been done in humans. In some small studies, people consuming a calorie-restrictive diet (under 1,400 calories daily) for five or more years had better heart function and lower blood pressure than those who consumed a diet of more than 2,000 calories daily. It is not clear whether the benefits come only from calorie restriction or from the increased fruits, vegetables, and whole grains consumed on most of these diets.

Resources

D'Adamo, Peter, and Catherine Whitney. Aging: Fighting It With the Blood Type Diet: The Individual Plan for Preventing and Treating Brain Decline, Cognitive Impairment, Hormonal Deficiency, and the Loss of Vitality Associated With Advancing Years. New York: Berkley Trade, 2006.

Delaney, Brian M., and Lisa Walford. The Longevity Diet. New York: Marlowe & Company, 2005.

Gates, Donna and Lyndi Schrecengost. The Baby Boomer Diet: Body Ecology's Guide to Growing Younger: Anti-Aging Wisdom for Every Generation. Carlsbad, CA: Hay House 2011.

Goode, Thomas. The Holistic Guide to Weight Loss, Anti-Aging, and Fat Prevention. Tucson, AZ: Inspired Living International, LLC, 2005.

Walford, Roy L., and Lisa Walford. The Anti-Aging Plan: The Nutrient-Rich, Low-Calorie Way of Eating for a Longer Life—The Only Diet Scientifically Proven to Extend Your Healthy Years. New York: Marlowe & Company, 2005.

Willcox, Bradley J., and D. Craig Willcox. The Okinawa Diet Plan: Get Leaner, Live Longer, and Never Feel Hungry. New York: Clarkson Potter, 2004.

EveryDiet.com. “The Longevity Diet.” http://www.everydiet.org/diet/longevity-diet (accessed June 24, 2012).

“50+: Live Better, Longer. Aging Well: Eating Right for Longevity.” WebMD. http://www.webmd.com/healthy-aging/features/aging-well-eating-right-for-longevity (accessed June 24, 2012).

Scientific Psychic. “Calorie Restriction Diet.” http://www.scientificpsychic.com/health/crondiet.html (accessed June 24, 2012).

Walford.com. “Getting Started On The Anti-Aging Diet.” http://www.walford.com/aastart.htm (accessed June 24, 2012).

American Aging Association, 25373 Tyndall Falls Dr., Olmsted Falls, OH 44138, (440) 793-6565, Fax: (440) 793-6598, americanaging@gmail.com, http://www.americanaging.org.

Calorie Restriction Society International, 187 Ocean Dr., Newport, NC 28570, (877) 481-4841, http://www.crsociety.org.

National Institute on Aging, Bldg. 31, Rm. 5C27, 31 Center Dr., MSC 2292, Bethesda, MD 20892, (800) 222-2225, TTY: (800) 222-4225, Fax: (301) 496-1072, www.nia.nih.gov.

Ken R. WellsTish Davidson, AM

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