1. Arm Yourself with Knowledge: Metabolism Basics
Broadly defined,
metabolism includes all of the physical and chemical changes that occur
inside the cells of the body and that maintain life. All activity in
the body occurs through the process of metabolism, in which cells break
down chemicals and nutrients to generate energy and form new molecules
such as proteins. Efficient metabolism requires blood loaded with
oxygen, glucose, and nutrients. Enzymes are the molecules that make
metabolism happen, and nutrients are the vitamins and minerals that act
as essential coenzymes. When a nutrient is deficient in the body,
certain metabolic functions are impeded and symptoms of disease can
arise. Your metabolism is influenced by:
• Age: Metabolism naturally slows about 5 percent per decade after age thirty.
• Gender: Men generally burn more calories at rest than women.
• Muscle mass: The more lean muscle you have, the higher your metabolic rate.
• Activity level: The more you exercise, particularly aerobically, the higher your metabolic rate.
• Genes: There can be an inherited aspect; some people have sluggish metabolic rates.
• Thyroid function: You could have an overactive or underactive thyroid, but this is uncommon.
The
good news: If you eat a balanced, healthy (low-fat) diet, add exercise
(lots of exercise), and keep your body in top running form, your
metabolism will burn calories like a top-flight engine. That’s why we’ll
cover a wide range of topics that have to do with maximizing your over
all health, nourishing your body, and exercising, all of which will help
you get your body functioning at its maximum capacity and boost your
metabolism!
2. Understand the Three Components
The term metabolism refers
to the way your body processes and utilizes the food you eat, not to
the amount of time required to do so. In other words, it’s not how fast
you metabolize food, but how efficiently you convert food into energy.
The process of metabolism consists of the following three components:
1. Basal
metabolism: 60 to 65 percent of the calories you eat daily provide the
basic energy you need to stay alive—breathing, circulating blood, organ
functioning, adjusting hormonal levels, growing and repairing cells, and
so on. Even if you lie on your sofa all day, your body will burn these
calories to support basic body functions. How many and how efficiently
you burn calories to meet these needs is called your basal metabolic
rate (BMR).
2.
Physical activity: 25 percent of your calories support movement and
physical activity. The frequency and intensity of physical activity can
positively or negatively affect this aspect.
3.
Food processing: 10 percent of calories are expended ingesting,
digesting, absorbing, transporting, and storing your caloric intake.
This is called the thermic effect, or the energy your body expends
processing the food you eat. For example, if you eat 2,000 calories a
day, approximately 10 percent, or 200 calories, will be used eating and
digesting your food.
3. Understand the Two Primary Processes
Most of the
food you eat is digested and then converted into energy through the
process of metabolism. This process, experts say, involves a complex
network of hormones and enzymes that not only convert food into fuel but
also affect how efficiently you burn that fuel. Within it, there are
two contrary, yet complementary, simultaneous processes:
• Catabolism.
This is the breaking-down process. Your body creates energy by
deconstructing digested food or stored fat into simpler substances so it
can use them in other ways. Fats are broken down into glycerol and
fatty acids. Carbohydrates are broken down into glucose, galactose, and
fructose and used as the primary energy that fuels the body during the
day. Proteins are broken down into amino acids, which the body uses to
rebuild or repair tissues.
• Anabolism.
This is the building-up process. Your body uses energy from glucose and
other molecules to build cells, move muscles, and carry out other vital
functions. For instance, the glucose from carbohydrates can be used to
make glycogen chains, the glycerol and fatty acids from fats can form
triglycerides, and the amino acids from proteins are used to remake
other proteins.
4. Understand How Metabolism Processes Food
The way
metabolism works is by causing a series of chemical reactions that break
down food. How it does this depends on whether the food is a
carbohydrate, protein, or fat. Without getting too clinical, it’s
helpful to know the basics:
1.
Carbohydrates are absorbed as simple sugars, mostly glucose. When your
body needs energy, it breaks down this glucose into a metabolite known
as pyruvate. Depending on the amount of available oxygen, pyruvate is
then converted either anaerobically (without oxygen) into lactic acid
for short bursts of energy, or aerobically (with oxygen) into acetyl CoA
a molecule that creates a slower, more long-term source of energy.
Lactic acid may also be recycled back into glucose, but acetyl CoA
cannot.
2. During
the digestive process, proteins are broken down into amino acids, which
are then converted into building blocks for hormones, nucleic acids
(part of DNA), digestive enzymes, and antibodies. Though an amino acid’s
primary role is to develop and repair other proteins, it may also be
used for energy and broken down into different metabolites. To be
processed, amino acids are broken down further into pyruvate or into
acetyl CoA, or they are moved into the citric acid cycle inside the
mitochondria.
3. In the
metabolic process, fats and oils are broken down into glycerol and fatty
acids. Glycerol can either be built up to make glucose or broken down
to form pyruvate. Like glucose, this pyruvate can then be used to form
lactic acid or acetyl CoA. Fatty acids are broken down in a process
known as beta, or fatty acid, oxidation, which produces acetyl CoA.
During beta-oxidation, oxygen combines with fragments of the fatty acid
to release electrons into the electron transport chain. Unlike glycerol,
fatty acids cannot be used to create glucose.
Since
all three of the main energy-producing nutrients can be broken down
into acetyl CoA, they can all be used to generate fat, which the body
can use as energy, or they can be stored in fat cells for future use.
5. Know the Winning Formula for Weight Maintenance
The
winning formula to maintaining your weight is that as long as the
amount of calories you consume equals the amount of calories you expend,
your weight should remain steady. If you are taking in more calories
than your body can metabolize and burn as energy and you want to lose
weight, you will have to reduce the amount of calories you take in,
increase the number of calories you burn through physical exercise, or
most likely do both. It is difficult to lose weight without changing the
output side of the metabolism equation; that is, you need to boost your
metabolism and increase its efficiency by eating healthfully and by
exercising regularly and rigorously.
6. Determine Your Metabolic Rate
One
of the first steps to take when embarking on a health and fitness plan
is to determine how many calories your body burns every day. This rate
is your metabolic rate, or the rate at which your body burns calories.
This number will give you a concrete idea of how many calories you need
to maintain your current weight, or how many you need to cut to lose
weight. Cornell University offers a Metabolic Calculator that is based
on your gender, age, height, weight, and activity level.
7. Understand Why Your Metabolic Rate Drops with Weight Loss Surprisingly, the more weight you carry, the faster your
Surprisingly,
the more weight you carry, the faster your metabolism. Having to carry
around the extra weight forces your metabolism to fire up. Sounds good,
but this creates that infamous weight-loss wall. As you lose weight,
your body doesn’t need to work as hard to metabolize food into energy,
so it slows down the process. This accounts for the day every dieter
experiences when the needle on the scale seems stuck and unlikely ever
to move southward again. Unfortunately, the only way to combat this
plateau is to stick with the diet and increase the amount and/or
intensity of your workouts. The slimmer you become, the fewer calories
you’ll need to maintain good health—deal with it.