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Metabolism is a natural process that defines all living things. Some believe that metabolism is the key to life itself. As early as several thousand years ago, ancient Greeks, Romans, Egyptians and Indians understood the importance of metabolic function, and were already exploring natural ways (including herbal therapy, fasting and relaxation methods) to manipulate metabolism for healing purposes.

Most scientists will tell you that today we know more about metabolism than we did thousands of years ago. But I question that. Certainly, we have much more data today on the chemical science of metabolism, but knowledge is more than memorized and analyzed scientific data. And life knowledge becomes useful only when we have the wisdom to draw (and then employ) useful conclusions.

In spite of all the information and all the prescriptions offered by modern diets, American people just keep getting fatter. In my mind, this suggests that our knowledge about metabolism is missing something – perhaps some of the old wisdom that kept hundreds of generations of people slender and strong. Of course, having access to modern scientific knowledge is enormously helpful too. The key lies in integrating these two bodies of wisdom, and then applying them to get a better understanding of our entire physiological landscape.

Let’s start with most people’s biggest metabolic concern – fat. Obesity is the result of compromised metabolism, and the inverse is also true: A healthy metabolism tends to keep you naturally lean. In order to understand the dynamics of fat gain and loss, however, we must acquire an intimate understanding of metabolic function.

The Metabolic Process

Metabolism is a living energetic cycle, a cycle in which energy is converted into material and material is converted into energy. The energy-into-material process is called anabolism. In this process the body deposits material (such as protein or fat) for tissue repair, muscle building or energy storage.

The material-into-energy process is called catabolism. In this process the body removes material while releasing energy. This includes the burning of fat or lean tissue and subsequent removal of toxins and waste (e.g., lactic acid) from the body. Healthy metabolism is created when these two vital processes, anabolism and catabolism, occur in proper balance, thus creating a desirable level of metabolic efficiency.

As noted, anabolism and catabolism are necessary for all living energetic cycles. If one of these processes is compromised, there will naturally be some diminution of health and life energy. When metabolic inefficiencies occur, all living systems – such as digestion, elimination, immunity and circulation – wind up being compromised. The body simply can’t function as it should and responds instead with all kinds of unpleasant conditions, including lethargy, fat gain, water retention, blood sugar imbalances, chronic disease and accelerated aging.

The 12 Factors That Affect Metabolism

1. Sympathetic and Parasympathetic Nervous Systems

Two key parts of our autonomic nervous system (ANS) – sympathetic and parasympathetic – are responsible for controlling our metabolic processes. The sympathetic nervous system (SNS) is responsible for all “fight and flight” reactions and is mainly catabolic (converting material into energy). The parasympathetic nervous system, on the other hand, is responsible for digestion and elimination and is mainly anabolic (converting energy into material).

When activated simultaneously, these two systems can be antagonistic. Many people who eat while under stress, for example, find that it results in digestive difficulties or exhaustion. When the adrenal “fight or flight” system contradicts the demands of the digestive system, more delicate metabolic problems may also occur. A compromised SNS converts less material into energy and this improper digestion can lead to the malabsorption (and thus deficiencies) of vital nutrients. This condition, in turn, eventually leads to low energy, poor immunity, allergies and weight fluctuation. (To understand how stress operates in your body — and how to reduce stress and build resilience — see “The Science of Stress“.)

2. Diet and Nutrition

Food supplies us with nutrients that are critical for healthy metabolism, and for health in general. Vitamins, minerals, essential amino acids, essential fatty acids and probiotics are all essential nutrients, many of which cannot be produced by the body and must therefore be ingested from an outside source.

Other nutrients, such as plant enzymes, flavonoids and phytochemicals are equally vital for protection and support of metabolic systems. These essential nutrients work synergistically, nourishing the body and building its internal systems.

Proteins, fatty acids, minerals and vitamins are building blocks for all tissues, organs, bones, hormones, neurotransmitters and enzymes. They also supply material for energy production and protect the body from free radicals and metabolic waste. Missing even one essential nutrient from your diet could have a devastating effect on your metabolism and overall health, so it’s important to understand how they work.

3. Minerals

Minerals (such as calcium, magnesium, copper and zinc) are critical for all tissue structures, including bones, skin and hair. They also play vital roles as electrolytes, which regulate the body’s electrical charge. That electrical charge is necessary for all cellular metabolic functions, but especially for the assimilation of nutrients and the elimination of toxins.

Proper mineral balance helps moderate our body’s sodium levels, preventing water-retention, inflammations and bloating. It also maintains our body’s proper acid/alkaline balance (overacidity leads to sluggish metabolism and makes the body more vulnerable to infection and disease). Minerals even help protect the body from radioactive toxins.

Because mineral deficiencies are related to serious metabolic problems (with symptoms such as indigestion, headaches, nervousness, depression, exhaustion and impotence), it is wise to eat plenty of mineral-rich foods, including fruits and vegetables grown in mineral-rich soil, as well as seafood and especially sea vegetables.

4. Proteins

Proteins—and the essential amino acids they contain—are the body’s chief building material. Adequate protein is absolutely necessary for healthy metabolism. However, to be useful, it must be properly digested and assimilated by the body (we’ll address this point in more detail later).

Good sources of complete protein (protein that includes all nine essential amino acids) are animal foods such as chicken, beef, eggs, cheese, fish and seafood. Soy is an alternative for those who wish to minimize their meat and dairy intake, but carefully combining foods is an equally good alternative. In times of short meat supply, ancient people traditionally used the combination of grain and legumes (such as rice and beans) to produce a complete-protein meal. All through the Roman Empire, in fact, beans were considered to be the “poor man’s meat” and were also the gladiators’ main food.

(You know you need protein to build muscle, manage your metabolism, and support tissue repair. But how much? What kind? And can you get too much? Our experts answer your top-12 questions about protein at “Protein Power: What You Need to Know“.)

5. Essential Fatty Acids (EFA’s)

Essential fatty acids (omega-3 and omega-6) are vital for all bodily functions, and particulary important as building blocks for prostaglandins (hormones that regulate blood pressure, control inflammation and pain and support energy production, including fat burning).

EFA deficiency may cause insulin insensitivity, which negatively affects the conversion of carbohydrates into energy. Many nutritionists recommend eating fatty fish (such as salmon, tuna and mackerel) as a natural source of EFAs. However, that recommendation tends to ignore the fact that most cooking methods (including frying, poaching and baking) destroy most or all of the fish’s sensitive oils.

Taking supplemental EFA oils (such as flaxseed and primrose) is therefore highly recommended. (See “What You Need to Know About Essential Fatty Acids” for more.)

6. Probiotics

Probiotics, such as lactobacilli, are the friendly flora (i.e., bacteria) that live in your intestines. They assist with digestion and, at the same time, inhibit all sorts of dangerous, unfriendly organisms that would otherwise take over your digestive tract.

Probiotics help digest proteins. They also neutralize toxins in the colon. When protein isn’t fully digested, it may reach the colon and bloodstream in a toxic form. When that happens, metabolism is compromised. Allergic reactions, irritable bowel symptoms and other pathological complications can result.

Naturally fermented foods (such as yogurts with acidophilus) are a good source of friendly bacteria. Probiotic supplements are another option.

(Our health experts address common questions about probiotics at “Everything You Need to Know About Probiotics“.)

7. Enzymes

Enzymes are involved in all metabolic processes. These protein compounds work as catalysts to break down foods into nutrients that can then be assimilated or converted into energy. They also work systematically as mediators and catalysts to other hormonal, glandular and sexual functions.

In the presence of adequate and balanced nutrition, the body produces its own enzymes. However, enzyme deficiencies often occur, most often as a result of too much processed and cooked food and too little live, raw food present in the diet.

Some enzyme deficiencies are also related to aging. The older you get, the fewer enzymes your body produces. Conversely, there is some evidence that supporting your body with enzymes may actually help slow the aging process.

In the blood, enzymes work as antioxidants and also as anti-inflammatory agents. Some believe that protease enzymes (enzymes that digest protein) have anti-cancerous properties. Studies show that lipase (an enzyme that breaks down fat) may help accelerate fat burning.

There is a rule of nature that raw foods contain all enzymes necessary for their own digestion. Therefore, natural sources of the fat-burning enzyme lipase can be found in high-fat raw foods such as avocados, nuts and seeds. Those who want to maximize their enzyme intake can also take plant-enzyme supplements.

(Should you add a digestive enzyme to your supplements? Find out at “Digestive Enzymes“.)

8. Vitamins

“Vita,” in Latin, means life. Vitamins, as the root word implies, are life carriers. They are involved in all metabolic processes, including energy production and assimilation of nutrients for the regeneration of tissues. One of the main functions of vitamins is to protect the body from harmful free radicals and toxins that are the natural byproducts of metabolism.

Vitamins and minerals work together synergistically in a precise biological balance. Vitamin deficiencies or imbalances may force the body to compromise all metabolic processes. Vitamin deficiencies also leave the body vulnerable to the damage of free radicals, which can in turn lead to tissue breakdown, disease and aging.

9. Phytonutrients

Phytonutrients, including chlorophyll, polysaccharides, sterols, saponins and lactones, are part of a huge variety of plant compounds that actively support certain metabolic processes. There are thousands of known phytochemicals, and a great deal of current research on the potential uses of these natural substances for medical purposes.

Herbs, a rich source of phytonutrients, have been used for thousands of years as metabolic enhancers and as tonics to help people recover from disease. While it would take pages to even begin to address the different functions of common herbs, let me briefly mention just a few things. Certain herbs, such as panax or Siberian ginseng, may help balance metabolic disorders and help alleviate stress-related and sexual problems. Other herbs, such as ephedra, have traditionally served as energy enhancers and fat burners.

Coffee and black tea are the most popular stimulant substances in the world. Green tea is a milder stimulant, but it contains highly potent antioxidants (polyphenols).

Before using any herbs, do your own research on processing, potency, standardization and possible side effects. (See “16 Phytonutrient Superstars” for some of the key phytonutrients you need.)

10. Fiber

Fiber plays a critical role in digestion, elimination and energy production. Besides helping detoxify the body through elimination of waste and toxins, fiber influences certain metabolic processes, including the conversion of carbohydrates and fats to energy. In short, fiber slows the absorption of simple sugars, thereby helping to stabilize blood sugar, regulate insulin activity and supply a steady stream of energy to the body.

Certain fibers (such as mucilage and pectin) work like sponges, pulling toxins and fat away from the body so they can be more quickly eliminated as waste. For people who don’t know when to stop eating, fibrous foods can also be helpful in triggering a full, satiated feeling.

Although fiber cereals and supplements are a good way to enhance your fiber intake, consider whole foods your first line of defense. Our bodies are built to metabolize whole foods, which are naturally rich in fiber and essential nutrients. Serious metabolic problems, including excessive fat gain, are often the result of chronic consumption of over-processed, refined food. Diets deficient in fiber and minerals make people crave for the missing nutrients, which leads to a near-constant sense of hunger, and sometimes to compulsive binging.

11. Exercise

Exercise is the most effective method for instantly boosting metabolism. Combining exercise and proper diet naturally leads to maximum metabolic efficiency.

Both are absolutely essential. That said, I believe that diet should be your No. 1 priority. Here’s why: Both your ability to exercise and your exercise results will naturally accelerate in the presence of proper nutrition. Without proper diet, you won’t be able to effectively access energy stores, nor will you be able replace nutrients lost during exercise. When that happens, metabolism declines.

I see a lot of people who go to the gym almost religiously. Often, they spend hours working out, and still, over the course of months, they show little or no progress. Every day, I see all these familiar faces huffing and puffing – but they’re still overweight in spite of their efforts. On the other hand, I know people who work out far less and make amazing progress, and still others who maintain a healthy, lean look without even trying.

Naturally, genetics are a key factor. But so is metabolism, and metabolism is inherently dependent on how you treat your body. If you attempt to exercise intensively without supporting your body’s nutritional needs, you won’t get very far.

Rest and relaxation, too, are every bit as important as action. Remember that under chronic stress or exhaustion, your body’s nervous system (and thus your metabolism) suffers. Avoid compulsively long daily exercise routines. Instead, vary your workouts, including short, intense training sessions in the mix.

Many popular health gurus recommend moderate exercise, such as walking or gardening, as the best solution. Their reasoning is that moderate exercise puts less pressure on the body and the heart. Certainly, gentle exercise is good for you, and it results in less oxidation and fewer free radicals than intensive exercise, but it also limits the challenges you can approach and the level of fitness you can achieve.

I believe the best way to exercise is by providing your body with intense stimuli to which it will naturally adapt. Our body has the wisdom to adjust to physical strain by getting stronger and tougher. Through this adaptative process, the body improves it’s own metabolic state.

Intense and short exercise intervals are also effective in pumping blood and oxygen to the entire body. Maximum oxygenation helps rejuvenate all body tissues and, again, this helps boost overall metabolism.

Nourish your body, exercise intensely and get enough rest, and you can quickly reach a state of maximum metabolic efficiency.

If you haven’t been exercising regularly and strenuously, don’t try to force yourself to exercise with maximum intensity straight out of the gate. Instead, follow a constructive exercise routine in which you gradually increase intensity over a period of weeks or months.

Nourish your body, exercise intensely and get enough rest, and you can quickly reach a state of maximum metabolic efficiency. In this state, your body will efficiently burn body fat as fuel. Its base level of energy utilization will accelerate, and gradually, this will cause your body to naturally redesign itself.

When you reach maximum metabolic efficiency, you are literally re-creating yourself – at a cellular level – on an ongoing basis. Just because you weren’t born with a super-fast metabolism doesn’t mean you can’t possess one. And just because you are carting around extra fat right now doesn’t mean you have to keep it forever.

If you want to live in a young, vigorous, lean body, just give your body what it needs in order to reach a peak metabolic state: Eat well, exercise intensely, get enough rest. Most importantly, get to know your body from the inside out. Enjoy its power, respect its complexity, and it will repay you richly.

12. A Few Words on Stubborn Fat

Fat burning is probably the No. 1 national health topic. Almost everyone is interested in burning fat. Unfortunately, most people who lose fat quickly gain it back, and then some. The rebounding and weight fluctuations make people desperate and discouraged. And then there is “stubborn fat” – that stuff that just doesn’t seem to go away, even when you drop a lot of weight.

Stubborn-fat gain is usually age-related. Starting in their mid-30s, men typically accumulate it in the belly and chest. Women get it around the butt, hips and thighs. However, stubborn fat isn’t always a product of age alone. Today, it is an increasingly serious problem for many young people, too.

As we’ve seen, fat metabolism is affected by many factors such as hormonal balance, enzyme availability, insulin sensitivity, essential fatty acid balance – even glandular and neural functions. Essential nutrients, enzymes, exercise and rest are all factors that can influence fat gain or loss.

We also know that fat burning occurs when the catabolic state is dominant. The most popular way to reach a dominant catabolic state is through a low-calorie diet or fasting. However, these dietary methods can be dangerous and are generally destined to fail because they inevitably cause a decline in the body’s metabolic rate. The body adapts to the lower intake of calories by slowing itself down. When metabolism declines, symptoms such as sensitivity to cold, exhaustion, and depression often occur.

The best way to burn fat without digging oneself into a sluggish-metabolism hole is by actively reversing this trend – forcing the body to become more metabolically efficient, instead of less.

How do you do this?

When all the factors that influence metabolism – such as complete nutrition, enzyme loading, detoxification, exercise and adequate rest – are activated, your body will naturally adopt a peak metabolic state. Your first job is to eat not just sensibly but intelligently. A steady supply of all essential nutrients should be your top priority. Take time to study how your body actually processes and reacts to the various substances you ingest. Don’t let ignorance of your own body become an excuse for your dissatisfaction with it.

Next, learn about your body’s natural rhythms and energy cycles and work with them, not against them. I personally believe that a healthy metabolic state is one in which the body naturally tends to burn more (not less) energy. That is to say that, ideally, your body should be in a slightly catabolic state during most of the day.

Naturally, during the working hours (when you’re running around, solving problems and battling stressful situations), the fat-burning sympathetic nervous system (SNS) is dominant. If you don’t interfere with your biological clock by eating heavy meals during the day, you will let the SNS do its job. Light, healthy, periodic snacks (including small amounts of protein) will help keep your body from sinking into starvation mode. So eat when your system calls for fuel (and before your blood sugar drops). Just be aware that heavy meals will slam the lid on your catabolic state.

It is for this reason that I generally suggest having the largest meal late in the day. Everyone has differing opinions about this, and if you have already found a system that works for you, there is no need to change it. My personal approach involves eating minimally during the day and then feasting at night. I never count calories, I eat as much as I like and I maintain a natural body fat percentage of between 4 and 6 percent.

When and how you eat is up to you, but if you are having a hard time losing fat, I would simply encourage you to examine whether your eating schedule (or lack of one) may be part of the problem.

Working out on an empty stomach is another way to accelerate fat burning and simultaneously boost growth hormone production. When you exercise on empty, your body is forced to use fat storage as energy. If you eat before your workout, your body will use the meal that you ate as a source of fuel. On the whole, the more you force the body to adapt to turning material into energy, the more efficient it will become in burning fat as a body fuel.

As a final note I’d like to mention the importance of detoxification. When your body is loaded with toxins, all metabolic processes are compromised. The body will desperately try to keep the toxins away from vital organs such as the heart or the brain by dumping them into the fat tissue. This process, in my opinion, is one of the chief reasons for stubborn-fat gain.

Detoxification is imperative to healthy metabolism, in particular because it takes pressure off the liver and the lymphatic system. The liver plays a critical role in the process of fat metabolism and detoxification. Unfortunately, a congested liver can’t break down cholesterol or fatty acids properly. Detoxification methods such as periodical fasting, herbal therapy as well as habitual avoidance of rancid fats and other toxins can all help protect the liver and support healthy metabolic function.

A clean system is a healthy system, and a healthy system is efficient. Remember, the presence of significant stubborn fat deposits is a signal from your body that something is wrong. It’s a sign that something you are doing is throwing your body’s natural system out of balance. Your job is to rediscover and re-create that balance, and let your body take care of the rest.

This article originally appeared as “Metabolic Mystery Tour” in the November 2001 issue of Experience Life.

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