What is Metabolism?

Over the past couple of weeks we have had a look at both a healthy approach to weight loss and some of the top ingredients used in supplements to achieve weight loss.

What I want to do now is go back to basics and exam the root element associated with weight gain and weight loss. That element is Metabolism. Firstly let us exam the origin of the word.

Source: http://dictionary.reference.com/browse/metabolism?s=t)


1875-80; < Greek metabol (ḗ) change ( meta- meta- + bolḗ a throw) + -ism.

C19: from Greek metabolē change, from metaballein to change, from meta- + ballein to throw



The sum total of the chemical processes that occur in living organisms, resulting in growth, production of energy, elimination of waste material, etc. See anabolism, basal metabolism, catabolism


The sum total of the chemical processes affecting a particular substance in the body: carbohydrate metabolism, iodine metabolism

Derived Forms

metabolic (ˌmɛtəˈbɒlɪk) adjective

Metabolically, adverb

Metabolism is closely linked to nutrition and the availability of nutrients.

In the article “5 Metabolism Myths Debunked” (August 24, 2009) Sarah Whitman-Salkin she states “Metabolism is commonly understood to be the rate at which the body burns calories.” As would be expected Dr Ananya Mandal, MD has a more clinical description, “Metabolism is a term that is used to describe all chemical reactions involved in maintaining the living state of the cells and the organism.”

Both are in agreement when they point out that this is only half the truth as there are effectively two steps involved.

Metabolism can be conveniently divided into two categories:

  • Catabolism – the breakdown of molecules to obtain energy or destructive metabolism
  • Anabolism – the synthesis of all compounds needed by the cells or constructive metabolism


In Catabolism, cells break down those large molecules to release energy and dispose of waste. This energy release provides fuel for anabolism. In Anabolism, small molecules are changed into larger, more complex molecules of carbohydrates, proteins, and fats (the holy trinity of nutrition). Anabolism requires the input of energy, in the form of food calories, and is the process by which the body stores energy.

In this way, anabolism and catabolism exist in balance with each other and are the Ying and the Yang of metabolism.

Energy formation is one of the vital components of metabolism.

Nutrition, metabolism and energy

Nutrition is the key to metabolism. The pathways of metabolism rely upon nutrients that they breakdown in order to produce energy. This energy in turn is required by the body to synthesize new proteins, nucleic acids (DNA, RNA) etc.

Nutrients in relation to metabolism encompass bodily requirement for various substances, individual functions in body, amount needed, level below which poor health results etc.

Sarah Whitman-Salkin dispels a number of myths about metabolism. The first is:

Myth 1: Metabolism is genetic and can’t be changed. False. Well, partly false. All humans (and actually all living things) are born with the ability to break down food in order to create energy. In this sense, metabolism is genetic and is as unique as a fingerprint, and while some people metabolize food very fast and others very slow.Whether metabolism is “fast” or “slow” is determined by metabolic rate, called basal metabolic rate or BMR, which is the amount of calories one burns while at rest.

Definition: Basal metabolic rate (BMR) refers to the minimum amount of energy — in the form of calories — that your body requires to complete its normal functions, such as breathing, breaking down food, and keeping your heart and brain working. Age, gender, weight, and physical activity directly effect on basal metabolic rate.

BMR varies from person to person and increases with your amount of muscle tissue. Someone with a low BMR will burn fewer calories while at rest, while someone with a high BMR will burn more calories while at rest

What’s burning the calories while the body is resting? Muscle and fat, though not equally. For every pound of muscle the body burns 35 calories a day, while for every pound of fat burns just two calories per day. Increased muscles and muscle density will lead to the body burning more calories, which in turn will raise the body’s BMR. So weight training is a surefire way to raise BMR. But aerobic activity, too, will help the body to burn calories, not only from the immediate activity but also from the calories that will be used later, while the body is resting. Many people's BMR stays increased for approximately 48 hours following exercise. All this work will ultimately increase BMR. So even if slow metabolism is in your genes, you don’t have to live with it.

Metabolic Pathways

The chemical reactions of metabolism are organized into metabolic pathways. These allow the basic chemicals from nutrition to be transformed through a series of steps into another chemical, by a sequence of enzymes.

Enzymes are crucial to metabolism because they allow organisms to drive desirable reactions that require energy. These reactions also are coupled with those that release energy. As enzymes act as catalysts they allow these reactions to proceed quickly and efficiently. Enzymes also allow the regulation of metabolic pathways in response to changes in the cell's environment or signals from other cells.

Men have more lean muscle than women and also have larger organs than women, which means that while at rest men are burning more calories than women are. This means that across the board men have higher BMR simply because they’re men.

Myth 2:  is that metabolism is the same for men or women, no matter their ages that is doubly untrue. Its been said that muscle mass is your body’s fat burning furnace, and that the more muscle mass you have, the more calories you burn at rest. On average, men have nearly 10 percent higher BMR than women. And women have a layer of subcutaneous fat, which pretty much never goes away no matter how many crunches a girl does, and fat is always going to burn fewer calories than muscle. While men typically have a faster metabolism they don’t necessarily have more discipline.

Additionally, as people age metabolism slows down. This isn’t a function of age per se, but of muscle deterioration and the biological inclination toward weight gain. Here’s another happy fact for men: Men maintain muscle density longer than women, and so as a woman’s BMR declines (starting in her 40s) a man’s metabolism won’t slow until he’s at least a decade older.

Myth 3: is about some foods, for example hot peppers and green tea, being able to speed up metabolism which is completely false. There are no foods that will speed up metabolism. While some studies have shown that very spicy foods can cause a spike in metabolism, that spike won’t last and after about 30 minutes the rate of metabolism will be back where it started. And even if that spike were appealing, the metabolic process wouldn’t speed up in such a way as to influence weight loss. Since weight loss is the result of more energy being spent than consumed, a spike in metabolic rate will help the body burn calories more quickly but will not affect overall metabolism in a noticeable way.

So what can you eat to burn calories and jump-start your metabolism? The short answer is “a balanced diet,” which means foods that are high in protein and low in carbohydrates and fat. Here’s the basic science behind carbs: The body easily converts simple carbohydrates (such as fruit, sweets, and soda) and sugar into glucose, which is absorbed into the bloodstream. As the amount of glucose in the body increases, the pancreas responds by producing insulin, a hormone that moves the sugar from the blood into cells where it can be stored as energy. The non-scientific term for this process: sugar rush. The unintended consequence: weight gain. Insulin is your body’s fat storing hormone.

Key#1 of Eric Reardon MS, CNC &

Certified Nutritionist 5 KEYS TO SUCCESSFUL WEIGHT LOSS is – Regulate Your Insulin Levels

“Insulin is your body’s fat storing hormone and when you eat high glycemic carbs like pasta, rice, potatoes, breads, cereals and sugar you are raising insulin levels. Too much insulin locks the doors to the fat cells, making fat burning next-to-impossible. You can regulate insulin by eliminating sugar and processed carbs, and eating quality protein, fat and vegetables.”

Simple carbs elevate insulin, increase hunger, promote fat storing, and increase the risk of many disease states and inflammatory conditions such as cardiovascular disease and type II diabetes.” The same is not true of complex carbs, however, which take more energy for the body to convert into glucose. Complex carbs such as whole grain bread, whole grain pasta, and starchy vegetables are slower to convert to glucose than simple carbs because they haven’t been refined, or already broken down, as white sugars have. The more time the body takes to convert carbs to glucose, the longer the body will feel full, and the harder metabolism will be working to break down the carbs. High-fiber, slow-burning carbs keep insulin in balance, which keeps your body out of a fat-storing mode, regulates energy, and provides a sense of satiety.

The ultimate pro-metabolism food is protein: poultry, fish, eggs, nuts, seeds, and legumes such as beans and lentils. Metabolism breaks down proteins into amino acids, which the body uses to maintain muscles, blood, and body organs (all things that help keep BMR high). Protein is vital for survival. Protein is a part of every cell in your body, and no other nutrient plays as many different roles in keeping you alive and healthy. Protein is also much more difficult for the body to break down than simple or even complex carbs, and requires about 25 percent more energy for digestion. This means that in the process of breaking down protein-packed foods, the body is expending lots of energy, which ultimately helps increase metabolism in the long run.

Myth 4: Eating one big meal per day will boost metabolism. There have been a number of studies on this topic in recent times and the general consensus has been that eating small, frequent, multiple meals with the concentration on whole foods with minimal processing are best. The reason being that metabolic rate will ultimately slow down when you starting skipping meals or not eating. Without sufficient nutrients, cells will readjust and begin to function on smaller amounts of energy, which they can do only by storing more fat in anticipation of these periods of nutrient deprivation. By eating frequently you keep your blood sugar stable, which will reduce cravings, and keeps your metabolic rate high, and consistently nourishes the body with crucial vitamins and minerals.

The advantage of eating say five or six small, low-calorie, high-protein meals throughout the day the body’s energy supply will be constant and calories will be steadily converted into energy, which means metabolism will be working hard and BMR will be speeding up.

Myth 5: Everything eaten after 7 p.m. turns to fat. Not true. Eating after a certain time does not automatically mean that you are going to store that food as fat. Though metabolism slows down while the body is sleeping, metabolism never stops working entirely. One of the reasons that this rule was made so popular is that it’s an easy way to control late-night binging and unhealthy nighttime snacking.

If you’re hungry after 7 or 8 or even 9, you should eat, but eat healthfully.

When you wake up in the morning, your body hasn’t ingested a single thing in six to nine hours, and as a result metabolism has slowed by about 15 percent. Your metabolism won’t speed up until the body can produce energy, which comes from the ingestion of calories.

Remember: metabolism is all about the give and take, the Ying and Yang, of energy consumption and energy production. Balance is key.

Carbohydrates in Metabolism

Foods supply carbohydrates in three forms: starch, sugar, and cellulose (fiber). Starches and sugars form major and essential sources of energy for humans. Fibers contribute to bulk in diet.

Body tissues depend on glucose for all activities. Carbohydrates and sugars yield glucose by digestion or metabolism.

Most people consume around half of their diet as carbohydrates. This comes from rice, wheat, bread, potatoes, pasta, macaroni etc.

Proteins in Metabolism

Proteins are the main tissue builders in the body. They are part of every cell in the body. Proteins help in cell structure, functions, haemoglobin formation to carry oxygen, enzymes to carry out vital reactions and a myriad of other functions in the body. Proteins are also vital in supplying nitrogen for DNA and RNA genetic material and energy production.

Proteins are necessary for nutrition because they contain amino acids. Among the 20 or more amino acids, the human body is unable to synthesize 8 and these are called essential amino acids.

Foods with the best quality protein are eggs, milk, soybeans, meats, vegetables, and grains.

Fat in Metabolism

Fats are concentrated sources of energy. They produce twice as much energy as either carbohydrates or protein on a weight basis.

The functions of fats include:

  • Helping to form the cellular structure Nutrients;
  • Forming a protective cushion and insulation around vital organs;
  • Helping absorb fat soluble vitamins,
  • Providing a reserve storage for energy

Essential fatty acids include unsaturated fatty acids like linoleic, linolinic, and arachidonic acids. These need to be taken in diet. Saturated fats, along with cholesterol, have been implicated in arteriosclerosis and heart disease.

Minerals and Vitamins in Metabolism

The minerals in foods do not contribute directly to energy needs but are important as body regulators and play a role in metabolic pathways of the body. More than 50 elements are found in the human body. About 25 elements have been found to be essential, since a deficiency produces specific deficiency symptoms.

Vitamins are essential organic compounds that the human body cannot synthesize by itself and must therefore, be present in the diet. Vitamins particularly important in metabolism include:

  • Vitamin A
  • B2 (riboflavin)
  • Niacin or nicotinic acid
  • Pantothenic Acid etc.



So there you have it. I sincerely hope that you now have a better understanding of the mechanics and functionality of metabolism, particularly when it comes to general health and weight loss. Fundamentally it’s more about Ying and Yang than it is about smoke and mirrors.






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