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2. the sum of the physical and chemical processes by which living organized substance is built up and maintained (anabolism), and by which large molecules are broken down into smaller molecules to make energy available to the organism (catabolism). Essentially these processes are concerned with the disposition of the nutrients absorbed into the blood following digestion.

There are two phases of metabolism: the anabolic and the catabolic phases. The anabolic, or constructive, phase is concerned with the conversion of simpler compounds derived from the nutrients into living, organized substances that the body cells can use. In the catabolic, or destructive, phase these organized substances are reconverted into simpler compounds, with the release of energy necessary for the proper functioning of the body cells.

The rate of metabolism can be increased by exercise; by elevated body temperature, as in a high fever, which can more than double the metabolic rate; by hormonal activity, such as that of thyroxine, insulin, and epinephrine; and by specific dynamic action that occurs following the ingestion of a meal.

The basal metabolic rate refers to the lowest rate obtained while an individual is at complete physical and mental rest. Metabolic rate usually is expressed in terms of the amount of heat liberated during the chemical reactions of metabolism. About 25 per cent of all energy from nutrients is utilized by the body to carry on its normal function; the remainder becomes heat.
basal metabolism the minimal energy expended for the maintenance of respiration, circulation, peristalsis, muscle tonus, body temperature, glandular activity, and the other vegetative functions of the body.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.


1. The sum of the chemical and physical changes occurring in tissue, consisting of anabolism (those reactions that convert small molecules into large), and catabolism (those reactions that convert large molecules into small), including both endogenous large molecules as well as biodegradation of xenobiotics.
2. Often incorrectly used as a synonym for either anabolism or catabolism.
[G. metabolē, change]
Farlex Partner Medical Dictionary © Farlex 2012


1. The chemical processes occurring within a living cell or organism that are necessary for the maintenance of life. In metabolism some substances are broken down to yield energy for vital processes while other substances, necessary for life, are synthesized.
2. The processing of a specific substance within a living cell or organism: iodine metabolism.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.


The sum of the processes by which a chemical or biomolecule is handled by the body.

The biochemical alteration of substances introduced into the body.

The sum of all physical and chemical processes involved in producing (anabolism) and consuming (catabolism) bioactive compounds to maintain life.

The manner in which a drug is acted upon—taken up, converted to other substances and excreted—by various tissues.
Segen's Medical Dictionary. © 2012 Farlex, Inc. All rights reserved.


1. The sum of the chemical and physical changes occurring in tissue, consisting of anabolism, those reactions that convert small molecules into large, and catabolism, those reactions that convert large molecules into small, including both endogenous large molecules as well as biodegradation of xenobiotics.
2. Often incorrectly used as a synonym for either anabolism or catabolism.
[G. metabolē, change]
Medical Dictionary for the Health Professions and Nursing © Farlex 2012


The totality of the body's cellular chemical activity, largely under the influence of enzymes, that results in work and growth or repair. The ‘building-up’ aspects of metabolism are known as anabolic and the ‘breaking-down’ as catabolic. Metabolism involves the consumption of fuel (glucose and fatty acids), the production of heat and the utilization of many constructional and other biochemical elements provided in the diet, such as AMINO ACIDS, fatty acids, carbohydrates, vitamins, minerals and trace elements. The basal metabolic rate is increases in certain disorders, such as hyperthyroidism, and decreases in others. Anabolism can be artificially promoted by the use of certain steroid make sex hormones (androgens or anabolic steroids).
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005


the sum total of the chemical processes occurring in cells by which energy is stored in molecules (ANABOLISM) or released from molecules (CATABOLISM), life being maintained by a balance between the rates of catabolic and anabolic processes. All metabolic reactions occur in steps, in which compounds are gradually built up or broken down. Each step of the ‘metabolic pathway’ is catalysed by a different enzyme whose structure is coded by a specific gene, the end product being called a ‘metabolite’. A special energy-carrying molecule called ATP is involved in these processes. See BASAL METABOLIC RATE.
Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005


All the physical and chemical changes that occur in cells to allow growth and maintain body functions. These include processes that break down substances to yield energy and processes that build up other substances necessary for life.
Gale Encyclopedia of Medicine. Copyright 2008 The Gale Group, Inc. All rights reserved.


Sum of chemical and physical changes occurring in tissue, consisting of anabolism (those reactions that convert small molecules into large), and catabolism (those reactions that convert large molecules into small), including both endogenous large molecules and biodegradation of xenobiotics.
[G. metabolē, change]
Medical Dictionary for the Dental Professions © Farlex 2012

Patient discussion about Metabolism

Q. How is it possible to have permanent weight loss if dieting slows down metabolism? well, i know that eating less will have the body adjust to the new calorie intake and thus, no further weight loss. So how is it possible to have permanent weight loss if eating less doesn't work? Please give tips and suggestions, people who have successfully lost weight. thanks so much!

A. That is why you need to cycle every few weeks. Change things up and shock your body because it does plateau. But if you challenge yourself every so often you will see results continuously.

Q. How could one boost metabolism by diet? I am aware for long that metabolism is the cause for poor health and fitness.So how could one boost metabolism by diet?

A. Metabolism, if it is not erroneous genetically; then it can be controlled or increased by any diet. What matters is the timing and regularity you feed yourself which uses your hormones and enzymes in your body to do the task they are for. This timing and regularity depends on eating in same time regularly and working and sleeping too. To excite some hormones even if they had switched off their action in body, can be excited by exercise and feeding with small diets in regular short time intervals. To make all this happen, reduce on junk foods, please.

Q. How does coffee affect a diet? does it have an affect on metabolism? on losing weight?

A. Well, coffee can increase and to accelerate the beginning of burning fat during exercise (usually only after 20-30 minutes of exercise), but the overall effect is not that substantial. YOu should remember that it makes your kidney to produce more urine, so you should drink more.

More discussions about Metabolism
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References in periodicals archive ?
"Those with smaller body frames, who are shorter and may have difficulty holding on to muscle mass, tend to have lower metabolisms," Elizabeth Lowden, a bariatric endocrinologist at the Northwestern Medicine Metabolic Health and Surgical Weight Loss Center at Delnor Hospital, told ( Popsugar .A
Previous research worked on the principle that body temperature and metabolism were closely aligned because metabolism is the primary source of heat and the body temperature itself affects the metabolic rates.
If you're looking to improve your metabolism, eating a balance of macronutrients (protein, fats, and carbohydrates) will help support healthy hormone levels.
The IMSR is also very active in training the next generation of clinician and basic scientists in the area of metabolism. Dr Manolopoulos said: "We provide educational opportunities, starting from summer projects for biomedical and medical students of the University of Birmingham, to full clinical and scientific training for doctors and scientists who want to do research in metabolism.
effects on metabolism had nothing to do with caffeine, saying instead
If you have a slower metabolism, you'll burn less glucose and fat, and may gain weight if your energy intake is more than your energy expenditure.
The researchers began their study by testing many amino acids in rat liver cells (the liver is a crucial organ in glucose metabolism).
The second phase of the study reports results from 53 healthy, non-obese men and women between ages 21 and 50 who cut calories by 15% over 2 years and underwent additional measurements for metabolism and oxidative stress.
showed that LSG affects the amino acid and lipid metabolism. It leads to modification of amino acids and lipid metabolism as indicated by changes in glycerol-phosphatidylcholines and SM levels [41].
(5) Department of Endocrinology and Metabolism, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong 250021, China
In metabolic pathways associated with alanine, aspartate, and glutamate metabolism, similar changes in [alpha]-ketoglutaric acid were observed before and after exercise, while levels of fumaric acid decreased after exercise (Figure 6).