Macronutrients are essential nutrients—carbohydrates, proteins, and fats—that the
body needs for energy and proper growth, metabolism, and function. They are called
“macro” because we need these nutrients in large quantities compared to the micronutrients
(vitamins and minerals), which are needed in smaller quantities. In this
section I will explain the various macronutrients, recommended intakes, and the best
food sources.
Macronutrients provide us with calories as follows:
Carbohydrate: 4 calories per gram
Protein: 4 calories per gram
Fat: 9 calories per gram
For example:
If a food product contains 10 g of carbohydrate, 2 g of protein, and 1 g of fat per serving,
it would provide 10 × 4 = 40 calories from carbohydrate, 2 × 4 = 8 calories from
protein, and 1 × 9 = 9 calories from fat for a total calorie count of 57 calories per serving.
PROTEIN
Protein is a necessary component for building, maintenance, and repair of many body
systems and processes, including:
• Production of collagen and keratin, which are the structural components of bones, teeth,
hair, and the outer layer of skin; they help maintain the structure of blood vessels
• Manufacture of hormones, such as insulin and thyroid hormone
• Production of enzymes that control chemical reactions in the body
• Proper immune function—production of antibodies, white blood cells, and other
immune factors
• Transportation of oxygen, vitamins, and minerals to target cells throughout the body• Source of energy—the liver can use protein to make glucose when there is not enough
carbohydrate available, such as when you skip a meal or follow a low-carb diet.
Food Sources
Protein is found in animal products, nuts, legumes, and, to a lesser extent, in fruits
and vegetables. When we eat protein the body breaks it down into amino acids, some
of which are called essential because they must be provided by the food we eat.
Others that can be produced by the body are called non-essential.
Protein from animal sources contains all of the essential amino acids. Therefore,
your best sources of lean protein are chicken, turkey, fi sh, and eggs. Choose freerange
and organic wherever possible to reduce ingesting harmful hormones and
chemicals.
Plant proteins do not contain all the essential amino acids and are considered
incomplete proteins. It is possible, though, to combine various plant proteins to get all
the essential amino acids. For example, eating oats, lentils, and sunfl ower seeds either
together or separately throughout the day provides all the essential amino acids. You
could also combine whole-wheat pasta with white kidney beans or tofu with brown
rice to get all the necessary amino acids. It just requires careful meal planning.
There are certain advantages of eating plant over animal proteins—they provide
fi bre and phytochemicals (antioxidants), do not contain saturated fat, and
may play a role in disease prevention. Soy protein, for example, has been shown to
signifi cantly lower cholesterol and triglyceride levels, and protect against bone loss.
A number of studies have found lower risk of chronic disease in those who eat a
plant-based diet.
The Institute of Medicine recommends ranges for macronutrient intake that are
associated with a reduced risk of chronic disease while providing adequate intake
of essential nutrients. They suggest that adults get 45–65 percent of calories from
carbohydrates, 20–35 percent from fat, and 10–35 percent from protein. Ranges for
children are similar, except that infants and younger children need a slightly higher
proportion of fat (25–40 percent).
CARBOHYDRATES
Carbohydrates are the body’s main source of fuel—glucose, which is needed by every
cell in our body. They also provide valuable nutrients (vitamins, minerals, and essential
fatty acids) and fi bre, which is important for intestinal health.
Food Sources
There are two classes of carbohydrates—simple and complex. Simple carbohydrates
include naturally occurring sugars in milk and fruit, and refi ned sugars (granulated
sugar). There is a major difference among these simple carbohydrates: fruits offer
a range of nutrients and fi bre, while refi ned sugars provide empty calories and lack
nutritional value. Excess sugar consumption is linked to dental caries, obesity, insulin
resistance, high triglycerides, low HDL (good) cholesterol, and compromised immune
function. The World Health Organization recommends reducing sugar intake to below
10 percent of total calories. Aside from candy and baked goods, sugar is also found in
pop, condiments (ketchup, barbecue sauces), juices, ice cream, and other sweets.
Complex carbohydrates include starches and indigestible dietary fi bre. Starches
are found in bread, pasta, rice, beans, and some vegetables. Today many of our
starches are refi ned and processed, which strips the food of its fi bre and nutrients. For
example, white bread, pasta, and rice are much less nutritious, so choose the brown
or whole-grain products.
Dietary fi bre is found in fruits, vegetables, beans, and the indigestible parts of
whole grains such as wheat and oat bran. In addition to supporting intestinal health
and proper elimination, fi bre also improves blood sugar balance, lowers cholesterol,
reduces the risk of colon and breast cancer, and plays a role in weight management.
The recommended intake of fi bre for adults 50 years and younger is 38 g for
men and 25 g for women; for men and women over 50 it is 30 and 21 g per day,
respectively, due to decreased food consumption. Sadly, most people get only onethird
to one-half of the recommended amount. To boost fi bre intake, incorporate
more raw vegetables, fruits, whole grains, and legumes in your diet and consider a
fi bre supplement.
Glycemic Index
The glycemic index (GI) is a scale that measures how quickly carbohydrates are broken
down into sugar. Those that are broken down quickly—such as simple carbohydrates
and refi ned starches—have a high GI. Foods that are broken down slowly—such as
most vegetables, fruits, and unprocessed grains—have a low GI.
Numerous studies have linked high-GI diets to obesity, insulin resistance, type 2 diabetes,
and increased risk of heart disease. Eating high-GI foods can lead to blood sugar
imbalances that may result in fatigue, increased appetite, and food cravings. For these
reasons, it is best to minimize high-GI foods and maximize your intake of low-GI foods.
See Appendix B for more information on the GI and the rating for common foods.
FATS
“Fat” has become a negative word as it is associated with obesity, yet we do need a
certain amount of fat in our diets and on our bodies. The point to keep in mind is that
there are good fats and bad fats.
The good fats are the unsaturated fats, namely, the monounsaturated fats (olive,
canola, and peanut oil) and polyunsaturated fats. The polyunsaturated fats provide
us with essential fatty acids (EFAs), which are broken down into two groups:
• Omega-6 fatty acids: Linoleic acid (LA), which is converted into gamma-linolenic
acid (GLA) and arachidonic acid (AA)
• Omega-3 fatty acids: Alpha-linolenic acid (ALA), which is converted into eicosapentaenoic
acid (EPA) and docosahexaenoic acid (DHA)
The body cannot make EFAs, so they must be obtained through diet or supplementation.
They are essential for many body processes and functions, including:
• Growth and development of brain, nervous system, adrenal glands, sex organs, inner
ear, and eyes
• Energy (fat is the most concentrated source of energy)
• Absorbing fat-soluble vitamins (vitamins A, D, E, K, and carotenoids)
• Maintaining cell membrane integrity
• Regulation of cell processes such as gene activation and expression, enzyme function,
and fat oxidation
• Production of hormones and chemical messengers
Food Sources
Here is a breakdown of the EFAs and their sources:
• LA: Found in vegetable oils such as saffl ower, evening primrose, sunfl ower, corn,
hemp, canola, and olive oil.
• GLA: Found in borage, blackcurrant, and evening primrose oils.
• AA: Found in meat and eggs. We get adequate AA through diet. Too much of this
fat is not good, as it causes infl ammation.
• ALA: Found in fl axseed and hemp oil and, to a lesser extent, in nuts, green leafy
vegetables, wheat germ, and blackcurrant seeds.
• EPA and DHA: Found in fatty fi sh, such as salmon, mackerel, herring, cod, sardines,
and tuna.
There is great controversy over what constitutes the optimal dietary intake ratio of
omega-6 to omega-3 fatty acids. It is estimated that we currently get around 15:1,
whereas leading EFA authorities recommend a ratio closer to 4:1 or even 2:1.
The Institute of Medicine has set an adequate intake level for linoleic acid for
adults 19–50 years of age at 17 g/day for men and 12 g/day for women; alpha-linolenic
acid at 1.6 g/day for men and 1.1 g/day for women. These levels are lower for
younger and older individuals.
Rather than trying to calculate the perfect ratio or intake, aim to have more
omega-3s (fi sh, fl axseed, hemp, and fi sh oils) and GLA (borage, blackcurrant, or
primrose oil) from diet and/or supplements, as these are the benefi cial fats that are
commonly defi cient.
Diets rich in the omega-3 fatty acids offer cardio protection by lowering blood
cholesterol and triglyceride levels, reducing blood clotting, and reducing the risk of
heart attack and sudden death. These fats also reduce infl ammation and are helpful
for arthritis and other infl ammatory disorders. GLA also reduces infl ammation, and
prevents clotting, dilates blood vessels, improves skin health, and benefi ts those with
diabetes and arthritis.
SATURATED FATS
Saturated fats are found in animal products such as meat, poultry, milk, cheese, butter,
and lard, as well as in tropical oils (such as palm, palm kernel, and coconut oil)
and foods made from these oils. These fats are high in cholesterol and linked to heart
disease, high cholesterol, obesity, and cancers of the breast, colon, and prostate.
Most people get 38 percent or more of the day’s calories from fat while health
authorities suggest no more than 20–35 percent of which less than 10 percent comes
from saturated fat. To cut your intake of saturated fat, trim fat and skin from meat,
choose lean poultry over red meat, and low-fat cheese and dairy (cottage cheese, feta,
and hard cheeses have less fat). Butter is fi ne in moderation (see sidebar).
BUTTER VERSUS MARGARINE
For years margarine was considered to be a healthier alternative to butter, however
most margarines contain hydrogenated oils (trans fats), which are artifi cial processed
fats linked to heart disease and cancer. The exception is non-hydrogenated margarines,
such as Becel, which contain benefi cial plant sterols that can help lower cholesterol.
While butter contains saturated fats, they are short-chain saturates, which are easily
digested and provide a source of useable energy. Butter also contains nutrients: lecithin,
vitamins A and E, and selenium. So the bottom line is: Choose butter or a non-hydrogenated
margarine.
TRANS FATS
Trans fatty acids are naturally found in small amounts in animal products; however,
the majority of trans fats in our diet come from the artifi cial form. Trans fats are created
when oils undergo a chemical process called hydrogenation, which solidifi es
them. This is the process that makes vegetable oil into margarine. Trans fat is also
found in cookies, crackers, french fries, baked goods, and other snack foods.
When trans fats were fi rst introduced into our food supply, they were thought
to be a healthier alternative to saturated fats. Many years later this was found to be
false. Trans fats elevate cholesterol levels, increasing the risk for heart disease and
heart attack, and are also linked to cancer, particularly breast cancer. The Institute
of Medicine has stated that there is no safe limit for trans fats in the diet and that
we should reduce consumption of these dangerous fats. Food companies have been
making efforts in this area. You will now see many packaged foods labelled “trans
fat free.”
CHOLESTEROL
Cholesterol is a waxy substance found in the fats (lipids) in our blood. It is manufactured
in the liver and also obtained from consuming saturated and trans fats.
Cholesterol is not all bad—the body requires it to produce sex hormones, maintain
cell membranes, and for a healthy nervous system.
Aside from diet, cholesterol levels can be elevated by family history, lack of activity,
and liver disorders, and cholesterol consumption increases the risk of heart
disease.
As with fats, there is good and bad when it comes to cholesterol. The good
cholesterol is HDL (high-density lipoproteins) and the bad is LDL (low-density lipoproteins).
LDL cholesterol can build up in the artery walls of the brain and heart,
narrowing the passageways for blood fl ow, a process known as atherosclerosis, the
precursor to heart disease and stroke.
HDL cholesterol is called good cholesterol because it picks up the LDL deposited
in the arteries and transports it to the liver to be broken down and eliminated.
To lower LDL and raise HDL levels, exercise regularly, minimize saturated fats,
avoid trans fats, and don’t smoke (smoking lowers HDL).
TRIGLYCERIDES
Triglycerides (TG) are the chemical form in which most fats exist in food (both animal
and plant fats). They are also present in the blood along with cholesterol.
A diet that is high in fat, sugar, refi ned carbohydrates, and alcohol can elevate
TGs. Overeating also raises TG because excess calories are converted to fat in the
liver and then into TG to be transported in the blood. High levels of triglycerides are
associated with heart disease and diabetes. It is possible for triglycerides to be high
even when blood cholesterol is normal, so get your levels checked regularly. In most
cases, TG levels can be effectively managed with diet and exercise.
SUMMARY
In this section we learned that our bodies need a balance of quality protein, carbohydrates,
and fats. These macronutrients provide us with the energy and nutrients
needed for proper growth, development, and many body processes. In a later chapter
I will outline principles for a healthy diet—my top recommendations for a nutritional
plan for optimal health and disease prevention.