1. health and fitness
2. weight loss

Diet is Just A Four-Letter Word
By Stephen F. Barnes, Ph.D.
San Diego State University
Diet is just a four-letter word. At any given time an
estimated 75 million Americans are on some kind of formal
diet or weight loss plan at an annual cost of $69 billion to
them… and often frustrated with the slow progress they are
making, feeling overweight, and suffering in silence.
However, most of us are holding a “diet dance card,” that is,
going through the physical and emotional motions of
worrying about our weight even if we are not currently out on the floor with the real
fatties. It is estimated more than 70 percent of adults regularly consume reduced fat and
other so-called “better for you” foods for weight management, and over half are making a
concerted effort to reduce their calories or eat whole grain and fortified foods because
they have been convinced such behaviors are really good for them. “Better for you” foods
include diet, light, reduced cholesterol, reduced sodium, caffeine free, sugar free,
fortified, organic, and low carb varieties. The average American, according to National
Eating Trends, has at least two “better for you” products a day (NPD Group, 2008).
Having said all of this, how’s that diet going? Not too well…?
Happy with your current weight and body image? What, no comment…?
The Diet Craze
The history of human dieting is riddled with conjecture, bad science, and deception. In
fact, there are so many claims and counter-claims today about what to eat or not eat,
sandwiched between failed diets, it is a wonder the whole enterprise doesn’t simply
implode. But instead it keeps growing at about 6 percent annually. It includes diet centers
and programs, group and individual weight-loss plans, diet camps, prepackaged foods,
over-the-counter and prescription diet drugs, weight-loss books and magazines,
commercial and residential exercise clubs with weight-loss programs, sugar-free, fat-free,
and reduced calorie ("lite") food products, imitation fats and sugar substitutes, and
physicians, nurses, nutritionists, other health professionals specializing in weight-loss.
Key Concepts: Dieting
Dieting is the intentional practice of regulating one’s food
intake to achieve and maintain a desired weight threshold. Diets
to promote weight loss, as opposed to those designed for weight
gain, are often divided into one of the following types: lowcarbohydrate, low-fat, low-calorie, and very low-calorie.
There can be little doubt America has been and remains preoccupied with diet,
deprivation, and weight loss, as Susan Yager (2010) so ably chronicles in The Hundred
Year Diet. And, it remains to be understood how one of the best-fed nations in the world
developed some of the very worst eating habits.
Diet fads have come and gone over the years, like rain.
One of the earliest is attributed to William the Conqueror
who became too fat to ride his horse. He devised an
alcohol-only diet in 1087—which, of course, didn’t work.
Another interesting approach to overindulgence was an
1829 diet consisting caffeine-free drinks, vegetarian
cuisine, and the legendary graham cracker. Alas, today
Presbyterian minister Sylvester Graham is only
remembered for the graham cracker. Then in 1903 a selftaught nutritionist by the name of Horace Fletcher,
dubbed “The Great Masticator,” proposed that people should chew their food exactly 32
times before spitting it out—an effective dieting strategy that, for obvious reasons, really
didn’t catch on (Fletcher, 2009).
Other ineffective fad diets have consisted of the first belt-driven fat massager developed
in 1857 by Dr. Gustav Zander of Sweden, the invention of calorie counting in 1917, a
cigarette diet pushed by several tobacco manufacturers in the 1920s that reportedly
suppressed one’s appetite, a 1928 meat-and-fat diet based on the successful Intuit practice
of eating primarily caribou, raw fish and whale blubber (with less than 2 percent of their
diet coming from fruits, vegetables, and other carbs), the use of slimming soaps in the
1930s, a tapeworm diet in 1954 that was allegedly used by famous movie stars to keep
the weight off, and Dr. Herman Taller’s 1961 “Calories Don’t Count” diet that permitted
the unrestricted consumption of high protein, followed by ingesting three ounces of
polyunsaturated vegetable oil in pill form (Wolf, 2005).
Diet strategies currently making the rounds include gluten-free, 3 Day diet, and a
Lemonade diet and variety of other cleansing programs that claim to remove toxins from
your body. There is no serious scientific evidence behind any of these, of course. Here is
some good advice for spotting fad diets. Be particularly cautious of any weight-loss plan
that omits specific foods or food groups, identifies so-called “good” and “bad” foods,
promises a quick fix, or is based on testimonials and/or little or no scientific research
(WebMD, 2010a).
Here is a brief thumbnail sketch of some of the more recent diets that have worked well
for some people, actually resulting in weight loss (for a comprehensive diet survey see
WebMD, 2010b):
Low-carbohydrate Diets
• Atkins Diet, probably the most well-known and controversial low-carb diet, is
based on the theory that overweight people eat more carbohydrates than they need
for energy, with the unused portion being stored as body fat. By restricting
carbohydrates to a mere fraction of that found in the typical American diet (less
than 40 grams per day) the body enters a state known as ketosis, that is, it burns its
own fat for fuel. Over time, the transition from weight loss to weight maintenance
is made by gradually increasing carbs so long as gradual weight loss is maintained.
Exercise in all phases of the diet is now emphasized.
In a meta-analysis of 107 studies of low-carbohydrate diets, Bravda et al. (2003)
concluded that there currently was insufficient evidence to make recommendations
for or against the use of low-carbohydrate diets, particularly among participants
older than age 50 years, for use longer than 90 days, or
for diets below 20 grams/day or less of carbohydrates.
Among the published studies reviewed, weight loss
while using low-carbohydrate diets was principally
associated with decreased caloric intake and
increased diet duration but not with reduced
carbohydrate content.
Recent reviews of the Atkins diet have been more
critical (Janicek, Willenberg, & Gabel, 2009).
Rapid weight loss in the first two weeks on these
types of diets is due to diuretic water loss, not fat loss.
After the first two weeks the weight loss does continue, but only because of calorie
restriction from the reduction of consumed carbohydrates. But there are some health
consequences with ketosis: weakness, nausea, dehydration, light-headedness, irritability
and a decrease in appetite. Prolonged ketosis may leach calcium out of the bones,
increasing the risk of osteoporosis.
Key Concepts: Carbohydrates
The term carbohydrate, an organic compound, refers to any food rich
in starch (e.g., bread, pasta, beans, potato, vegetables, rice) or sugar
(e.g., fruit, soft drinks, candy). Carbohydrates are a major source of
fuel for humans, necessary for physical and mental activity, and organ
function. There are different types of carbohydrates that perform
various complex functions in our bodies, ranging from energy storage
to RNA production to immune system functionality. The liver breaks
down the most digestible carbohydrates into glucose that then enters
the blood stream and nourishes cells (Wikipedia, 2010; Harvard
School of Public Health, 2010).
Because low carbohydrate diets are usually high in total fat, saturated fat, and
cholesterol, the risk for developing heart disease and some forms of cancer may
also be increased. Additionally, high protein intake, more than 35% of calories
from protein consumption (e.g., in excess of 100 grams per day), puts enormous
strain on the liver and kidneys, especially for people with diabetes who are already
at risk for diabetic kidney disease.
After the low-carb diet has ended, people often gain back the
weight they previously lost. When carbohydrates are reintroduced
into the diet, the body will store them as fat in response to the
ketosis.
•South Beach Diet was invented by a cardiologist connected with at Mount Sinai
Hospital in South Florida, hence the name. It was originally developed for
overweight heart patients, but has spread across the country and has been a
consistent New York Times Bestseller. It begins with a two-week induction phase
in which most carbohydrates are avoided while meats, shellfish, chicken, turkey,
fish, nuts, cheese (fat-free), eggs, salads, and vegetables are readily consumed. The
result is an 8-10 pound weight loss similar to the Atkins Diet. In Phase Two some
foods avoided in Phase One are re-introduced but according to a specific meal plan
and recipes. Weight loss drops to 1-2 pounds per week. Phase Three is about living
a sensible lifestyle, eating healthy foods, and balancing “good carbs against bad
carbs” in order to maintain weight. The balancing is carried out on the basis of the
Glycemic Index (see Key Concepts, below).
Key Concepts: Proteins
Proteins (aka polypeptides) are organic compounds made up of chains
of 22 different amino acids. Proteins, via these amino acids, are
fundamental components of all living cells and every cell requires
protein in order to function properly. In humans, nine of these amino
acids, called essential amino acids, can only be obtained from eating
and digesting protein-rich foods—beef, poultry, fish, eggs, dairy, nuts,
seeds, and legumes. While humans can probably survive on a diet of
limited carbohydrates, they cannot live without a sufficient supply of
essential proteins from various foods.
Low-fat Diets (only 20-30% of daily calories come from fats)
• Weight Watchers is considered by some to be among the most consistent weight
loss programs over the past 40 years, helping literally thousands of people to lose
weight and keep it off. The newest version combines healthy nutrition, effective
calorie control, and livability. It teaches people how to eat smarter portions and
make healthier, more filling food choices. While no foods are prohibited each food
is assigned "points" based on its calorie, fat, and fiber content. Every dieter has a
targeted Daily Points Range based on their specific body weight and activity level.
Under this low-fat system, about two pounds per week can be shed. Much of the
success is due to the Weight Watchers support system that keeps dieters connected
to each other and support staff. Members can get support online and at meetings in
most communities. This fee-based program offers diet tools, recipes, restaurant
guides, meal trackers, and other helpful techniques.
• Jenny Craig diet, another well-known and popular program, is also low-fat by
promoting pre-packaged meals (mostly frozen) that are 60% carbohydrates, 20%
protein, and 20% fat, supplemented with fresh fruits and vegetables and low fat
dairy products. There are three levels to the program: 1) Dieters adjust to the
program by eating the foods they already like but in small portions; 2) Dieters
learn how to boost their energy and lose weight through regular physical activity;
3) Dieters learn how to continue with a healthy lifestyle
so that weight loss is maintained. Overeating is
regarded as largely an emotional issue, which can be
successfully addressed and managed by making
positive life changes. The ultimate goal of the Jenny
Craig program is to empower individuals to plan their
own menus so they can shop, cook and socialize with
foods.
Very Low-fat Diets (0-19% of daily calories come from fats)
•Pritikin Diet, introduced as a combined diet and fitness plan in the late 1970s,
advocates a very low fat/high fiber carbohydrate-rich diet based largely on
vegetables, grains, and fruits, and at least 30 minutes of daily aerobic exercise,
weekly weight training, and daily stretching. Dr. Nathan Pritikin’s book, also a
New York Times Bestseller, has sold more than 10 million copies worldwide. A
central principle in diet is caloric density. By eating low caloric density foods at
every meal (e.g., brown rice, oats, dark greens, potatoes, squash, beans, apples,
strawberries, and bananas) you can eat as much of them as you want. By
combining the leanest portions of animal protein with plenty of these vegetables
and fruits, you can reduce your caloric density and lose weight.
The Pritikin plan is consistent with numerous research outcomes that demonstrate
that regular exercise in combination with diet modification contribute significantly
to chronic disease reduction, including a diet based on whole foods high in fiber
and nutrient density along with the elimination of refined carbohydrates and fatty
foods (Roberts & Barnard, 2005).
It should be noted as well that proteins, per se, are not the problem. In fact, it is
possible that by eating more protein, especially vegetable protein, while cutting
back on easily digested carbohydrates benefits the heart. In a 20-year prospective
study of 82,802 women, those who ate low-carbohydrate diets that were high in
vegetable sources of fat or protein had a 30 percent lower risk of heart disease,
compared with women who ate high-carbohydrate, low-fat diets. But women who
ate low-carbohydrate diets that were high in animal fats or proteins did not have a
reduced risk of heart disease (Harvard School of Public Health, 2010).
Key Concepts: Glycemic Index (GI)
The Glycemic Index is a ranking of foods based on the rate at which blood
glucose levels rise when a particular food is consumed. Carbohydrates that
break down quickly during digestion, releasing glucose rapidly, have a high
GI; carbohydrates that break down more slowly, releasing glucose gradually
into the bloodstream and helping to keep blood sugar levels relatively
constant, have a lower GI. When blood sugar rises too high the brain signals
the pancreas to release additional insulin to compensate; excess glucose is
then stored as fat. GI is not related to portion size per se but the amount of
food consumed and how it is prepared creates a glycemic load that triggers
the body’s overall glycemic response. GI Examples:
Category
GI Index
Foods
Low
55 or less
Meat, grains, fruits and vegetables, nuts,
eggs, milk
Medium
56-69
Whole-wheat products, sweet potatoes,
long-rain rice, candy, ice cream, sucrose
High
70 and above
Potatoes, white bread, popcorn,
watermelon, glucose
Low-calorie Diets
•Slim-Fast Diet involves four steps to weight loss: portion control, sensible eating,
moderate physical activity (30 minutes per day), and diet support. The Slim-Fast
plan requires six small meals/snacks on a daily
basis. It is recommended that dieters consume
Slim-Fast products (diet shakes, soups, pasta, mealin-one bars, and nutritious snacks). Message
boards, online chats, success stories are designed to
provide timely encouragement. No calorie counting
is necessary and no specific foods are forbidden.
While you can still eat your favorite foods, the plan
emphasizes lean protein, fruits, and vegetables.
Key Concepts: Fiber
Dietary fiber is the indigestible part of plant foods. Fiber (aka
roughage), consisting of carbohydrates and a woody compound
known as lignin, alters the content of foods in the gastrointestinal tract
and changes how nutrients and chemicals are absorbed into the
bloodstream. There are two types of fiber, and plants contain both
types but in varying amounts. Soluble fiber sources include oats and
barley, legumes, vegetables such as broccoli, carrots, sweet potatoes
and onions, and some fruits, such as, bananas, berries, and plums.
Soluble fiber absorbs water and becomes gelatinous, and is then
fermented in the colon resulting in gases and active byproducts.
Insoluble fiber provides bulk, softens the stool, and shortens transit
time through the intestinal tract. Major sources of insoluble fiber are
whole grains, bran, nuts and seeds, potato skins, some fruits such as
avocados and bananas, and vegetables such as green beans, celery,
zucchini, and cauliflower.
Very low-calorie Diets
•Very low-calorie diet (VLCD) is typically a doctor-supervised diet that uses
commercially prepared formulas to promote rapid weight loss in patients who are
moderately to extremely obese, that is, with a body mass index (see Key Concepts,
below) over 30. The diet, usually in the form of liquid shakes or bars, replaces all
food intake for several weeks (or months) and can produce significant results, the
loss of 3-5 pounds per week and averaging 44 pounds in twelve weeks. Under
these extreme conditions dieters need to supplement
their intake with appropriate levels of vitamins and
micronutrients. People on a VLCD consume less than
800 calories per day and should also be enrolled in a
comprehensive weight-loss treatment program that
includes behavioral therapy, nutrition counseling,
managed physical activity, and/or drug treatment.
VLCD side effects often include fatigue, constipation, nausea, or diarrhea
but these conditions usually improve within a few weeks and rarely prevent
patients from completing the program. The most common serious side effect is
gallstone formation, which often develops in people who are obese, especially
women. Very little information exists regarding the use of VLCDs with older
adults, and care should be taken in their application with dieters over the age of 50
(U.S. Department of Health and Human Services, 2008).
What does all of this really mean? Are there some common denominators in all of these
diets? The simple answer is, “Yes.” By controlling portions (e.g., through meal
replacement) you control consumed calories. By limiting fat and starch intake you control
consumed calories. By burning more calories than you consume through increased
exercise and/or portion control you eventually lose weight. Bingo!
Key Concepts: Sugar (Sucrose)
Sugar refers to a type of digestible carbohydrate, characterized by a
sweet flavor, that is derived from sugar cane and sugar beets. Upon
ingestion, sucrose is an easily assimilated macronutrient that provides
a quick source of energy, provoking a rapid rise in blood glucose.
Over consumption of sucrose has been linked with adverse health
effects including tooth decay and an increased risk for chronic
disease. Research suggests that excessive consumption of sugarsweetened drinks along with physical inactivity may be linked to the
development of obesity, insulin resistance, pre-diabetes, and
metabolic syndrome.
“Miracle” Diet Drugs
Imagine taking a daily pill that sheds pounds without the need for exercise, improved
eating habits, or a lifestyle makeover. If it sounds too good to be true, it probably is.
The predecessors of today’s diet drugs often contained ingredients that were
accompanied by dangerous side effects. Amphetamine-based diet pills were popular in
the 1960s, but increased the user’s blood pressure and heart rate, created a serious
dependency problem, and often led to bouts of depression. In the 1970s an over-thecounter appetite suppressant, phenylropanolamine (PPA), became popular.
Unfortunately, it elevated blood pressure and caused hemorrhagic strokes in healthy,
young adults. It was pulled from the market by the FDA in 2000. Next came the wildly
popular fen-phen—the combination of phentermine and fenfluramine. Physicians wrote
millions of prescriptions each month only to learn later that there were life-threatening
side effects. Class action lawsuits followed as some users developed pulmonary
hypertension and heart valve disease. Billions in payouts
followed as drug makers experienced profound financial losses.
And, who can forget the Metabolife diet pill debacle in which
thousands of adverse effects and over 150 deaths were linked to
its ephedra-based “herbal dietary supplement,” finally banned
by the FDA in 2004.
Two diet drugs are currently available by prescription and several more are in the wings
undergoing clinical trials. Meridia (sibutramine) is an appetite suppressant and Xenical
(orlistat) is a so-called “fat-blocker.” These drugs can help you lose 5 to 20 pounds in six
months, with minimum side effects, provided you add regular exercise and healthier
eating to your daily regimen. By the way, Meridia, which alters your brain chemistry, can
also raise blood pressure and should not be taken by people on antidepressants or with
heart disease, liver, and kidney problems. Xenical disables pancreatic enzymes that are
involved in fat absorption. However, pushing fatty foods thru the intestines in this way
results in some inelegant side effects, such as, gas and rectal discharge. Since the drug is
taken with meals when they are consumed it doesn’t help with between-meal snacks, a
major issue for many over-weight individuals.
Off-label drug use, prescribing drugs that were not intended for weight loss but which
have it as a side effect, has been widely embraced by physicians and other health-care
practitioners, insurers, pharmaceutical companies, and even the FDA. The list includes
drugs originally intended for attention-deficit disorder, depression, diabetes, sleep
disorders, and smoking. Obviously, not everyone is a good candidate for weight-loss drug
therapy and, in off-label use, great care must be taken by both the physician and patient.
One commentator likened it to “medical bungee jumping” (Snyderman, 2009).
Why Diets Usually Don’t Work
Successful weigh loss involves five steps: you have to want to lose
weight to the point you are ready to make some basic life changes,
you must forget everything you think you already know about
weight loss, you must systematically eat less (portion control) but
eat more often, you must exercise a lot more, and get a good
night’s sleep. Weight regulation is a complicated bio-chemical
process that can be influenced by lots of factors under your
immediate control, such as, attitudes and habits of friends and
family, stress, emotional imbalance, hormones, taking certain
prescription drugs that work against weight loss, smoking, lack of exercise, eating
everything in front of you, and eating the wrong foods. This is why so many “wonderful”
diet regimes eventually fail. Dieters focus on one or two of these variables, as a rule,
ignoring the other important ones just listed. At the end of the day, the golden rule of
dieting is simply “calories in, calories out.”
What is a calorie, anyway? It is a measure of the energy potential in food. To get an idea
of how this works, think of your body as an “energy account” into which you make daily
deposits by eating food, converting it into energy, and making energy withdrawals as you
need them. The withdrawals involve burning calories on the basis of your basal
metabolism rate (BMR) (see Key Concepts, below) and through physical activity
(Snyderman, 2009).
To lose one pound you will need to burn about 3,500 calories. This can be done by eating
fewer calories, burning more calories through exercise, or a combination of both. The
chart below will give you some idea of what kinds of foods you would have to forego or
effort expended on a daily basis for one week in order to lose one (1) pound in weight.
Goal:
Lose one pound in
body weight @ 500
calories/day
Daily Food Strategy
Don’t eat large blueberry
muffin with butter
Daily Exercise Strategy
45-minutes of intense
cycling, Thai boxing
Don’t eat 4 ounces of
potato chips
45-minutes of rock
climbing
Don’t eat the Big Mac
45-minutes of step
Aerobics
Don’t eat two chocolate
iced donuts with sprinkles
Walk for one-hour at
3 miles per hour
No one said losing weight was going to be easy—and if they did, hang on to your wallet.
Key Concepts: Calories
Calories are units of energy, and are neither good nor bad. A single calorie refers to
the amount of energy necessary to raise the temperature of 1 gram of water one
degree centigrade. A food calorie is actually 1,000 calories, or the amount of
energy required to raise 2.2 pounds of water (one kilogram) 1 degree centigrade.
Calories come from only four types of food: carbohydrates, fat, protein, and
alcohol. Different foods contain different amounts of energy, or calories. For
example, carbs and proteins provide 4 calories per gram; alcohol provides 7
calories per gram; and fat provides 9 calories per gram. But calories are all the
same whether they are connected with celery, wheat bread, or chocolate.
Through a process known as metabolism the body breaks down food molecules
(organic matter) in order to release the energy (calories) within them in the form of
amino acids, fatty acids, and glucose. The body stores for future use energy it does
not need at the time of metabolism in the form of fat cells on your belly, thighs,
hips, buttock, arms. Increased activity—thinking, breathing, digestion, physical
activity--results in increased metabolism as bodily fuel needs rise. The opposite is
also true. Therefore, weight gain is the result of increased intake of food, decreased
activity, or some combination of both (The New York Times, 2010).
Do This, Get Free (and Slimmer)!
If you really, really want to lose weight (and it requires that level of personal
commitment), begin by critically assessing where you are on the Body Mass Index (see
Key Concepts, below). Understand that this is only an approximation that does not
actually measure body fat directly. This is, however, a useful screening tool. Also, be
mindful that BMI interpretations differ by age, gender, and ethnicity. Here are some other
important variations (Centers for Disease Control, 2010):
•
•
•
At the same BMI, women tend to have more body fat than men
At the same BMI, older adults, on average, tend to have more body fat than
younger adults
Highly trained athletes may have a high BMI because of increased muscularity
rather than increased body fatness
Key Concepts: Body Mass Index (BMI)
Body Mass Index (BMI) is a number that predicts with reasonable
accuracy the body fatness of most people. It is easily calculated from
your weight and height. Here is the formula:
2
weight (lb) / [height (in)] x 703
Calculate BMI by dividing your weight in pounds (lbs)
by height in inches (in) squared and multiplying
the total by a conversion factor of 703
Example: Weight = 150 lbs, Height = 5'5" (65")
Calculation: [150 ÷ (65)2] x 703 = 24.96
Next, go to the table below and determine where you fall along the
index.
Knowing your BMI is useful for at least two reasons. First, it gives you a starting point
for getting your weight (and life) under control. Second, it indicates important health risk
factors about which you should be aware. According to the National Heart, Blood, and
Lung Institute (1998), overweight and obese individuals are at increased risk for many
diseases and chronic health conditions, including:
• Hypertension
• Dyslipidemia (for example, high LDL cholesterol, low HDL cholesterol, or high
levels of triglycerides)
• Type 2 diabetes
• Coronary heart disease
• Stroke
• Gallbladder disease
•
•
•
Osteoarthritis
Sleep apnea and respiratory problems
Certain cancers (e.g., endometrial, breast, and colon)
BMI TABLE
BMI
WEIGHT STATUS
Below 18.5
Underweight
18.5 – 24.9
Normal
25.0 – 29.9
Overweight
30.0 and Above
Obese
So, now you know your BMI. What’s next? Actually, several things. You need to get
smarter about food (see Blog post, “You Are What You Eat…and Drink”), exercise, and
weight management. Calculate your Basal Metabolism Rate and daily caloric needs in
order to establish a caloric baseline (see Key Concepts, below). Weight and fitness goals
and milestones would be helpful. A life plan that engages a support network also works
well for many people. Consider one of the diets reviewed above or other good ones if you
need structure and encouragement. Also, there are some excellent websites out there
related to the topics and issues in this post, software applications, and calorie and exercise
monitoring devices (e.g., Garmin 205 and bodybugg).
Key Concepts: Basal Metabolism Rate (BMR)
Basal Metabolism Rate (BMR) is the rate at which you must burn
calories to maintain basic body functions—breathing, thinking,
digesting, sleeping--while doing little else. This is the minimum
caloric requirement needed to sustain life in a resting individual. Your
individual BMR accounts for up to 70 percent of your daily caloric
need but this percentage varies based on your actual metabolism rate,
gender, age, weight, body surface area, body fat percentage, diet, body
temperature/health, hormonal activity, and exercise level.
After calculating your BMR you can add an additional factor, level of physical activity, to
determine your total daily energy expenditure (TDEE). By combining both the BMR and
typical level of physical activity, you are able to establish a clear baseline for your daily
caloric needs. This is extremely useful for purposes of dieting since you can only burn fat
with a negative calorie deficit, that is, using more caloric energy than you are taking in
through the consumption of food. A calorie deficit can be created through diet, exercise,
or preferably a combination of both.
The BMR formulae below are reasonably accurate for all but the most lean/muscular and
obese individuals
BMR Calculation Formulae
Women: BMR = 655 + ( 4.35 x weight in pounds ) + ( 4.7 x height in
inches ) - ( 4.7 x age in years )
Men: BMR = 66 + ( 6.23 x weight in pounds ) + ( 12.7 x height in
inches ) - ( 6.8 x age in years )
BMR Activity Multiplier
Sedentary = BMR X 1.2 (little or no exercise, desk job)
Lightly Active = BMR X 1.375 (light exercise/sports 1-3 days/wk)
Moderately Active = BMR X 1.55 (moderate exercise/sports 3-5 days/wk)
Very Active = BMR X 1.725 (hard exercise/sports 6-7 days/wk)
Extremely Active = BMR X 1.9 (hard daily exercise/sports & physical job
or 2X day training, i.e. marathon, contest etc.)
Key Concepts: Calculating Your BMR
Calculating your BMR requires nothing more than basic arithmetic
skills. For example, let’s say you are 60 years old, male, 5’ 10” tall,
weigh 190 lbs., and are moderately active. Using the BMR formula
for males:
66 + (6.23 x 190) + (12.7 x 70) – (6.8 x 60)
or
66 + (1183.7) + (889) – (408)
or
2138.7 – 408
or
= 1730.7 (BMR calories)
1730.7 (BMR) x 1.55 (Activity Factor) = 2,682.6 calories per day to
sustain oneself. To lose weight, a diet deficit of 500 calories daily
would result in the loss of one pound per week.
The Most Effective Weight-Loss Strategy
The most effective weight-loss strategy combines regular, vigorous exercise with
choosing healthy foods in appropriate amounts.
In a recent meta-analysis of 43 different studies on exercise and weight loss, regular
exercise was an effective intervention, particularly when combined with diet management
(Shaw, Gennat, O'Rourke, & Del Mar, 2006). Exercise resulted in small weight losses
across all the studies. However, exercise combined with a low-calorie diet resulted in a
greater weight reduction than diet alone. Likewise, increasing exercise intensity increased
the magnitude of weight loss and there were significant benefits in other outcome
measures such as serum lipids, blood pressure, and fasting plasma glucose. Collectively
in this group of studies, exercise on average consisted of at least 30-minutes moderatelyintense activity on most days, such as, walking, jogging, cycle ergometry, weight
training, aerobics, ball games, and calisthenics. Since glycogen is preferentially burned
during the first 20 minutes of exercise, at least 30 minutes of exercise is necessary to
begin burning fat stores (Dachs, 2007).
Weigh Loss Is Independent of Diet Composition
Part of the dieting mythology that adds to the confusion about weight control is the
notion that certain foods are evil—like salty snacks, soft drinks, cookies, ice-cream. This
is the wrong approach. Food is fun, it’s part of life, and a lot of it tastes good.
You can eat just about anything so long as you do so responsibly. Remember, “every bite
counts!”
Eating fatty foods doesn’t make you fat. Eating a variety of foods in appropriate
proportions—fats, complex carbohydrates, protein, fruit, and vegetables---will help you
stay healthy and maintain the proper body weight for your age, height, and activity level.
However, there is substantial scientific evidence supporting the benefits of eating lean
proteins (e.g., fish, poultry), about 30 percent of your daily caloric intake, in association
with physical activity (Paddon-Jones, et al., 2008). Moderate protein diets, when
compared against conventional diets, which typically are high in carbohydrates, help curb
appetite and produce sustained weight loss along with favorable long-term changes in
body composition and blood lipids (Laymen et al., 2009).
Meal Frequency
For the past 40 years the question of the advantages, if any, of eating smaller but more
frequent meals has challenged nutritionists. As the theory goes, eating small meals
throughout the day while not increasing one’s caloric load can lower cholesterol, promote
weight loss, improve energy levels, boost metabolism, and preserve lean muscle mass.
The research findings are at best mixed, with some studies finding very modest decreases
in cholesterol levels and lower blood pressure from eating more frequently but no
specific energy advantage (Parks & McCrory, 2005; Bellisle, McDevitt & Prentice,
1997). On the other hand, there may be some negative health impacts from eating only
one meal per day or irregular eating. These include significantly higher blood pressure
and cholesterol levels (LDL and HDL), glucose intolerance, insulin insensitivity, and
lower cortisol levels, although the latter could be due to diurnal variations (Stote et al.
2007; Carlson et al., 2007; Farshchi, Taylor & Macdonald, 2005). Skipping meals or
engaging in intermittent fasting, despite lower caloric intake, appears to have more health
negatives than positives, and may actually reduce fat-burning metabolism.
This continues to be a very active research area. Questions needing clearer research
answers include both the timing of meals during the day and their frequency.
At a lifestyle level, eating more frequently while not increasing caloric intake can be
beneficial by increasing one’s food focus while decreasing hunger and snacking
throughout the day.
Key Concepts: Cortisol
Cortisol is a hormone produced by the adrenal gland, and is needed
for nearly all dynamic processes in the body, from blood pressure
regulation and kidney function, as well as glucose level maintenance,
fat building, muscle building, protein synthesis and immune function.
One of cortisol’s more important functions is to act in concert with
thyroid hormones at the receptor-gene level. Cortisol makes the
thyroid work more efficiently. A specific amount of cortisol—not too
high and not too low—is very important for normal thyroid function
(Virginia Hopkins Health Watch, 2009).
Aging and Weight Maintenance
As adults grow older their hormone levels change and metabolism slows down. Usually
their level of physical activity also declines which results in the replacement of muscle
mass with body fat. Together, these independent biological mechanisms often result in
weight gain for both men and women during their 50s and 60s, the dreaded middle age
spread (Evans & Cry-Campbell, 1997). The obvious solution, of course, is to move more
and eat less (portion control) and eat more frequently (4-5 times daily) (Williams &
Wood, 2006).
And for those motivated enough to engage in lifestyle
changes that will produce genuine weight loss, it is
critically important to avoid the diet roller coaster.
Going on a diet to lose weight only to gain to back
again is unhealthy and, simply, will make you crazy.
By the way, the number of fat cells we have stays
relatively constant across the lifespan after their
establishment in our teenage years (Spalding et al.,
2008). That means when you gain weight your existing fat cells get larger in terms of
volume. When you lose weight they shrink and become metabolically less active. Sorry.
Postscript Disclaimer:
All dietary and supportive lifestyle changes must be
personalized. Moreover, the research-based generalizations
offered here about dieting assume healthy adults, broadly
defined, who are motivated toward better weight management.
Individuals with special health issues, such as diabetes,
hormonal imbalance, or heart, liver, or kidney disease should
consult a physician or licensed dietician before embarking on
any weight-loss program.
Copyright 2010
Stephen F. Barnes, Ph.D.
San Diego State University Interwork Institute
Additional Reading
Synderman, N.L. (2009). Diet myths that keep us fat: And the 101 truths that will save
your waistline—and maybe even your life. New York: Crown Publishing.
Yager, S. (2010). The hundred year diet: America’s voracious appetite for losing weight.
New York: Rondale.
Informational Websites
About BMI for Adults (Centers for Disease and Prevention)
http://www.cdc.gov/healthyweight/assessing/bmi/adult_bmi/index.html
BMR Calculator
http://www.bmi-calculator.net/bmr-calculator/
Diets A-Z
http://www.webmd.com/diet/evaluate-latest-diets
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