CALERIE
Encyclopedia
CALERIE is a trial currently underway in the U.S. to study the effects of prolonged calorie restriction
on healthy human subjects.
The CALERIE study is being carried out at the Pennington Biomedical Research Center
(Baton Rouge, Louisiana), the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University
(Boston, Massachusetts) and the Washington University
School of Medicine (St. Louis, Missouri). It is hoped that caloric restriction reduces the incidence of cardiovascular disease
and cancer
and leads to a longer life, as has been demonstrated previously in numerous animal studies. CALERIE is the first study to investigate prolonged calorie restriction in healthy humans, which is practiced and advocated for by the members of the Calorie Restriction Society. Study subjects are selected from people who are not obese (because calorie restriction on obese people is already known to lengthen life, but possibly for different reasons).
A smaller predecessor study ended in 2006. Forty-eight subjects were randomly assigned to a control group and a treatment group; those in the treatment group were put on a 25% calorie reduction over a 6 month period. It was found that the treatment group had lower insulin resistance
, lower levels of LDL cholesterol, lower body temperature and blood-insulin levels as well as less oxidative damage to their DNA.
The second, larger, phase of CALERIE begain in 2007. The participants are subjected to a 25% calorie restriction over a 2-year period, and several physiological variables are regularly monitored. Participants are paid $5,000 at Tufts and Pennington and $2,400 at Washington University. As of October 2009, the study had 132 participants and was still accepting new ones.
Study subjects have to be highly motivated and organized enough to keep a detailed journal of all foods they eat. Their daily baseline calorie requirements are precisely determined before the trial: in a two-week laboratory test the rate of carbon dioxide
production is measured, allowing to compute the number of burned calories. The subjects are then taught a diet of low-energy density foods, such as vegetables, fruits (especially apples), insoluble fiber
and soups. Most subjects reported that they felt hungry for the first few weeks, after which they adjusted to the new diet. Complaints focused on the rigid bookkeeping scheme imposed on them.
Calorie restriction
Caloric restriction , or calorie restriction, is a dietary regimen that restricts calorie intake, where the baseline for the restriction varies, usually being the previous, unrestricted, intake of the subjects...
on healthy human subjects.
The CALERIE study is being carried out at the Pennington Biomedical Research Center
Pennington Biomedical Research Center
The Pennington Biomedical Research Center, located in Baton Rouge, Louisiana, is a campus of the Louisiana State University System and conducts both clinical and basic research. According to its website, its mission is to promote healthier lives through research and education in nutrition and...
(Baton Rouge, Louisiana), the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University
Tufts University
Tufts University is a private research university located in Medford/Somerville, near Boston, Massachusetts. It is organized into ten schools, including two undergraduate programs and eight graduate divisions, on four campuses in Massachusetts and on the eastern border of France...
(Boston, Massachusetts) and the Washington University
Washington University in St. Louis
Washington University in St. Louis is a private research university located in suburban St. Louis, Missouri. Founded in 1853, and named for George Washington, the university has students and faculty from all fifty U.S. states and more than 110 nations...
School of Medicine (St. Louis, Missouri). It is hoped that caloric restriction reduces the incidence of cardiovascular disease
Cardiovascular disease
Heart disease or cardiovascular disease are the class of diseases that involve the heart or blood vessels . While the term technically refers to any disease that affects the cardiovascular system , it is usually used to refer to those related to atherosclerosis...
and cancer
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...
and leads to a longer life, as has been demonstrated previously in numerous animal studies. CALERIE is the first study to investigate prolonged calorie restriction in healthy humans, which is practiced and advocated for by the members of the Calorie Restriction Society. Study subjects are selected from people who are not obese (because calorie restriction on obese people is already known to lengthen life, but possibly for different reasons).
A smaller predecessor study ended in 2006. Forty-eight subjects were randomly assigned to a control group and a treatment group; those in the treatment group were put on a 25% calorie reduction over a 6 month period. It was found that the treatment group had lower insulin resistance
Insulin resistance
Insulin resistance is a physiological condition where the natural hormone insulin becomes less effective at lowering blood sugars. The resulting increase in blood glucose may raise levels outside the normal range and cause adverse health effects, depending on dietary conditions. Certain cell types...
, lower levels of LDL cholesterol, lower body temperature and blood-insulin levels as well as less oxidative damage to their DNA.
The second, larger, phase of CALERIE begain in 2007. The participants are subjected to a 25% calorie restriction over a 2-year period, and several physiological variables are regularly monitored. Participants are paid $5,000 at Tufts and Pennington and $2,400 at Washington University. As of October 2009, the study had 132 participants and was still accepting new ones.
Study subjects have to be highly motivated and organized enough to keep a detailed journal of all foods they eat. Their daily baseline calorie requirements are precisely determined before the trial: in a two-week laboratory test the rate of carbon dioxide
Carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...
production is measured, allowing to compute the number of burned calories. The subjects are then taught a diet of low-energy density foods, such as vegetables, fruits (especially apples), insoluble fiber
Dietary fiber
Dietary fiber, dietary fibre, or sometimes roughage is the indigestible portion of plant foods having two main components:* soluble fiber that is readily fermented in the colon into gases and physiologically active byproducts, and* insoluble fiber that is metabolically inert, absorbing water as it...
and soups. Most subjects reported that they felt hungry for the first few weeks, after which they adjusted to the new diet. Complaints focused on the rigid bookkeeping scheme imposed on them.