The
Skinny On Popular Fad Diets
Do
You Know Fact From Fad? People are losing weight eating bacon and eggs-others
by eating only grapefruit or cabbage. Some claim to lose weight in their
sleep or by breathing differently. Are these diets safe and based on
scientific research? Or are marketing teams using isolated testimonials
to dazzle the public with a diet's reputed success? The following diets
are ten of the most popular on the market today. Click on each for an
analysis of the benefits and disadvantages of each and whether they
can be maintained for life.
Thousands
of diet plans contribute to a $40-billion-a-year weight-loss industry.
The public wants to get thin and the entrepreneur wants to get fat with
profits. Anyone can become a weight-loss guru with a hot marketing team,
a few choice testimonials and a smooth presentation. However, while
the weight-loss industry continues to grow, obesity has reached epidemic
proportions.
Most
diet plans are nothing more than low-calorie nutrition plans disguised
by clever marketing gimmicks. Scientific-sounding "facts" and hocus-pocus
"research" can dazzle and confuse the average consumer. Diet-plan marketers
go to great lengths to explain how their diet can work for everyone,
or claim that it is carbohydrate intake (or any other dieters "enemy-of-the-month)
that is the culprit. However, the bottom line is that a caloric deficit
(more calories burned than consumed) causes weight loss. The average
American consumes 300 calories more today than he did 30 years ago.
He also burns 260 less calories each day due to increased automation,
technology and sedentary occupations. Increased caloric intake and decreased
caloric expenditure means that the waistline of America is growing at
an alarming rate.
While
fad diets may initially offer rapid weight loss, the result is too often
temporary, leaving the dieter defeated, angry and often with a few extra
pounds just for good measure. The problem with fad diets is that they
are just that—fads. The key to long-term weight loss is adopting a healthy
lifestyle for life.
Dr.
Atkins Diet Revolution
This
best-seller claims that dieters can lose all the weight they want by
eliminating carbohydrates and sugar from their diets. With the lure
of eating "forbidden foods," Dr. Atkins charges that processed
carbohydrates and insulin, not excess calories, are responsible for
obesity in the United States. The low-carb, high-protein plan consists
of between 1,200 and 1,800 calories. This calorie range would result
in weight loss no matter what combination of foods (carbohydrate, protein
and fat) was employed.
Advantages:
The benefit to this diet is its simplicity and the fact that it is initially
enjoyable for dietary fat lovers. Additionally, sticking to the proper
calories (until the carbohydrate cravings overwhelm you) can be easy
because a person can only consume so much protein and fat before getting
sick of it for the day.
Disadvantages:
The downside to the plan is its reliance on protein. High-protein diets
put the body into a state of ketosis, causing headaches, bad breath,
nausea and carbohydrate cravings due to depleted glycogen stores. The
plan is too high in saturated fats and too low in fruits, whole grains,
calcium and fiber.
Plain
and simple - rebound, which is exactly what happened to everyone who
followed this same plan in the 1970s. The program did not work then
and it will have no lasting success now.
An
exhaustive search of peer-reviewed literature related to maintaining
weight loss, including the only true records located at the National
Weight Control Registry; revealed that not a single person accomplished
this feat with this exact or similar regime.
Is
this type of diet good for anyone?
If
a person had medical complications due to obesity and refused to exercise
and reduce calories appropriately for weight loss, a higher than traditionally
recommended protein and fat intake may be an alternative to ameliorate
symptoms.
*It
takes more than insulin to store fat. Insulin is a complex hormone with
myriad life giving functions and is only a mechanism that is used in
the accumulation of fat stores when a person supplies the calories.
The hormone does not cause the body to continually accrue fat unless
a person regularly eats too much. Since humans can not live 5 minutes
without insulin we must learn to live without eating in excess and then
looking for something else to blame it on.
Long-Term
Success:
Information from the National Weight Control Registry indicates that
high-protein, low-carbohydrate diets are not maintained for life. After
the initial weight loss, the dieter eventually rebounds if carbohydrates
are reintroduced into the diet.
Dr. Atkins
Diet Revolution was created by Robert C. Atkins, M.D.
Mastering
the Zone
Mastering
The Zone claims most people suffer from insulin imbalances that cause
them to gain weight. According Barry Sears, consumption of protein,
carbohydrate and fat in exact proportions, the imbalance is corrected
and excess weight drops off. Living in the Zone also can prevent heart
disease, diabetes, PMS, depression and cancer, according to Sears, who
also claims that this plan can slow the aging process. Average caloric
intake ranges from 1,000 to 1,700 calories per day.
Sears
states that carbohydrates stimulate the release of insulin* which affects
eicosanoids but neglects to tell you that protein also elicits an insulin
response. An eicosanoid is a hormone that among other functions helps
regulate inflammation, the blood's tendency to clot and the immune system.
Bad eicosanoids are the result of insulin release according to Sears'
book. No research exists to support Sears' proposed relationship between
performance, fatness, diet, insulin, bad eicosanoids and disease.
Advantages:
The plan recommends lean protein sources, minimizing consumption of
saturated fat. The typical American diet is not far from the 40/30/30
ratio of carbohydrate/protein/and fat.
One
advantage to this type of diet is that the carbohydrate recommendations
are higher than Atkins' plan. The typical American diet is not far from
the recommended 40/30/30 ratio of carbohydrate/protein/and fat and may
be ideal for certain individuals. However, just like the Atkins diet,
the Zone removes carbohydrates to achieve the lower caloric intake necessary
to promote weight loss.
Disadvantages:
Carbohydrates such as grains, fruit juices, pasta, starchy vegetables
and bread are not prohibited by serving sizes are minute (1/4 c. cooked
pasta, 1/8 c. baked beans, one-square-inch of corn bread). Choices,
combinations and portions can be odd and unappetizing. For example,
a snack choice includes two hard-boiled egg whites, half an apple and
three almonds.
The
concept is the same as other high-protein diets but less aggressive
and the smoke screen differs. Although the suggested foods are healthier
than the typical American diet and fall into a percentage they normally
eat, the science is incorrect and used to disguise the low-calorie recommendations.
Because calories are based on protein requirements, the number of calories
that the average female consumes on this food plan is approximately
975. For the average male, meanwhile, the amount is 1,700 calories.
Based on the first law of thermodynamics, at this caloric intake, weight
loss is guaranteed no matter what you consume. However, due to the very
low calories, long-term success would be very challenging, and there
is no such thing as a "one size fits all" diet as the author
claims.
*It
takes more than insulin to store fat. Insulin is a complex hormone with
myriad life giving functions and is only a mechanism that is used in
the accumulation of fat stores when a person supplies the calories.
The hormone does not cause the body to continually accrue fat unless
a person regularly eats too much. Since humans can not live 5 minutes
without insulin we must learn to live without eating in excess and then
looking for something else to blame it on.
Long-Term
Success:
Because the plan is based on very low calories and strict combinations
of protein, carbohydrate and fat at every meal, long-term success would
be very challenging.
Created
by Barry Sears, Ph.D.
Eat Right For Your
Type
Peter
J. D’Adamo, a licensed naturopath, claims that an individual’s
blood type should determine what foods to eat and which ones to avoid.
He asserts that when a particular blood type consumes "off-limit"
foods, the effect is akin to a transfusion of mismatched blood. His
theory attempts to tie the evolution of man to changing blood types
and diets. Recommended caloric intake varies widely from day to day.
The
rationale behind this plan is the biggest stretch of all and reaches
comic proportions. His theory tries to tie in the evolution of man with
changing blood types and diets. Any long term success with this plan
is an accident based on switching food intake to something more agreeable
to your digestive physiology or your frame of mind when you entered
the program (in other words, how important was it for you to lose weight).
Advantages:
The plan emphasizes lean sources of protein in addition to recommending
several servings of fruits and vegetables for all diets.
Disadvantages:
Current scientific research does not support D’Adamo’s claim
that blood type determines an individual’s response to certain
foods. Further, most critics of the plan cite the lack of a relationship
between blood type and disease as well as the false assumptions made
about the diet of early man. And, of course, there is no record of success
with this plan.
Long-term
Success:
Recommended menus include unusual and hard-to-find foods, and meal preparation
for families will varied blood types could prove challenging over the
long term.
Eat
Right For Your Type was created by Peter J. D’Adamo, N.D.
Sugar
Busters!
Similar
to Mastering the Zone and Dr. Atkins New Diet Revolution, the Sugar
Busters diet claims that carbohydrate (sugar) causes obesity and insulin
resistance in the United States. The authors advocate the elimination
of carbohydrate from the diet, claiming that one will not overeat foods
high in sugar and become insulin resistant. Again, by removing carbohydrate
and sugar from the diet, a significant number of calories are eliminated,
creating a caloric deficit and, thus, weight loss. An analysis performed
by the American Dietetic Association indicates that the menu plans recommended
in the book yield approximately 1,200 calories a day. It is not the
lack of carbohydrates that cause one to lose weight but rather the very
low calorie intake.
Advantages:
The authors recommend consuming lean cuts of meat in addition to fruits
and vegetables. Regular exercise is also encouraged.
Disadvantages:
Similar to other high-protein plans, rebound is inevitable due to eventual
carbohydrate cravings and the unrealistic restrictions proposed by the
diet.
The
deception here is brilliant because an increase in body fat can lead
to insulin resistance (IR). Therefore, lowering body fat with any method
can reverse IR.
They
make you believe that your carbohydrate intake (not weight gain) leads
to the IR and that starts the increase in body fat. By removing carbohydrates,
the calories decline, and succinctly body weight, leading to a reversal
of IR. The authors win because you lost weight and became insulin sensitive
again, but you lose because once you grow tired of protein and are starved
for carbohydrates, you will rebound with a vengeance.**
The
American Dietetic Association analyzed the recipes recommended by the
book and found that each menu averaged a mere 1,200 calories a day.
This is an unrealistic restriction on food intake that cannot be maintained.
Keep in mind that weight loss itself reduces the disease symptoms of
obesity; not necessarily the method in which one achieves it.
Long-term
success:
Due to inevitable carbohydrate cravings, long-range success is unlikely.
**The
bottom line is that this food plan is not the best way to lower your
food intake unless you are strictly throwing out junk food. You must
maintain a healthy balance of good carbohydrates within a caloric allotment
that promotes a healthy and desired level of body fat.
Sugar
Busters diet was created by: H. Leighton Steward, Morrison C. Bethea,
M.D., Sam S. Andrews, M.D., Ralph O. Brennan and Luis A. Balart, M.D.
Eat
More, Weigh Less
Contrary
to the wash of high-protein diets, this plan is very low in fat (10
percent of the total calories), high in carbohydrates and primarily
vegetarian in nature. The basic premise is that calories from fat cause
one to become fat; however, Dean Ornish does concede that calories consumed
above maintenance levels contribute to weight gain. The average amount
of calories ranges between 1,200 and 1,350 calories a day.
The
concept of this diet is based on dietary fat being responsible for weight
gain and its related diseases. Dr. Ornish did publish a study on this
type of food plan demonstrating that it can reduce and possibly reverse
heart disease in some individuals. It is unlikely that anyone could
argue that the suggested foods are not healthy. Epidemiological evidence
supports the health benefits of such foods and the replacement of dietary
fat with carbohydrates (grains, fruits and vegetables) will significantly
increase the volume of daily food intake while maintaining equal calories.
Advantages:
The benefit to this diet is that a small percentage of the population
would feel good with very low fat and high carbohydrates.
Disadvantages:
Studies by the National Weight Control Registry indicate that the majority
of those who have lost weight and kept it off were successful with a
diet comprised of 55 percent carbohydrate, 20 percent protein and 25
percent fat. This diet encourages minimal fat and protein intake. Again
like most other diets, by cutting down on a particular substrate, is
the easiest way to reduce intake when all other macronutrients are not
changed.
Long-term
Success:
Dietary fat is important to success for a number of reasons including
the transportation of vitamins, satiety (feelings of fullness) and the
simple pleasure of consuming food with some fat content. The bottom
line to any diet plan relates to the Law of Thermodynamics: When energy
(calories) in exceeds energy (calories) out, weight gain results. When
energy out exceeds energy in, weight loss is the result.
Eat
More, Weigh Less was created by Dean Ornish, M.D.
The Pritikin
Weight Loss Breakthrough
The
son of Nathan Pritikin, founder of the Pritikin Longevity Center, has
introduced a plan that encourages consumption of a very high volume
of complex, fibrous carbohydrates. His claim is based around the "Fat
Instinct," a biological drive to overeat high-fat foods and avoid
exercise.
Very
similar to Dr. Dean Ornish's Eat More, Weigh Less, the Pritikin plan
calls for limiting fat intake to 10-15% of your total calories, but
incorporates lean meats. His claim is based around the "Fat Instinct,"
which has been copyrighted for his program. He states that we consume
more fat due to a biological drive to conserve calories. Pritikin proposes
that we consume a very high volume of complex, fibrous carbohydrates.
Due to the high food-volume-to-calorie ratio of these types of foods,
stomach distention may occur quickly, leading to early meal termination
and thus a reduction in calorie intake.
Advantages:
The plan recommends choosing lean cuts of meats over higher-fat varieties.
This is sound advice and helps to lower caloric intake, which may reduce
the risk of coronary heart disease.
Regardless
of his theory, the plan includes healthy foods but has the same limitations
as the Ornish program. Very low-fat, high-carbohydrate diets are difficult
to maintain but may be appropriate for a small minority.
Disadvantages:
Due to the high volume of bulk in the diet, swelling of the stomach
occurs very quickly, leading to early termination of the meal, thereby
reducing the number of calories consumed. While a low-fat diet is certainly
healthful, very few people can stay satiated for a long period of time
on diet with only 10-15 percent of calories coming from fat. This may
lead to overeating and consumption of calories above a level necessary
for weight maintenance.
Always
beware of a "one size fits all" diet. Any time you remove
a significant portion of any macronutrient (protein, fat or carbohydrate),
it can sabotage your success by eventually causing an uncontrollable
desire to consume the missing food type, or worse, it may lead to cravings
you never had before
Long-term
Success:
Not everyone will feel good on such a low-fat diet. This will lead to
overeating of calories above maintenance levels and weight gain.
The
Pritikin Weight Loss Breakthrough was created by Robert Pritikin.
New
Cabbage Soup Diet
Claims
that one can lose as much as 20 pounds in seven days by following a
strict plan of a vegetable-based soup (consisting of cabbage, onions,
peppers, tomatoes, celery and onion soup mix) and one other specified
food. Because the plan consists of less than 1,000 calories a day, rapid
weight loss occurs. The author stresses throughout the book that this
type of diet should only be done for seven days.
Advantages:
Other than rapid weight loss, there are no advantages to this plan.
Disadvantages:
The downside to such an extreme approach to this method is weight loss
is temporary. Weight loss either represents water weight or lean body
tissue. Furthermore, many dieters report nausea, light-headedness and
gas as common side effects of the plan.
Long-term
Success:
Maintenance of the new weight is virtually impossible. Lifestyle changes
regarding healthy eating and exercise are not addressed in the plan.
The
New Cabbage Soup Diet was created by Margaret Danbrot.
The Grapefruit Diet
According
to various Internet sites, this diet is one of the most popular word-of-mouth
plans in the United States. Grapefruit is believed to have a fat-burning
enzyme and thus the plan calls for a grapefruit at every meal. Most
of the meals also include some protein (egg, chicken or beef), vegetables
and coffee or tea. Calories add up to about 800 a day, which leads to
dramatic weight loss.
Advantages:
The plus side to this diet is grapefruit is a great source of vitamin
C and high in fiber.
Disadvantages:
Any plan that restricts dieters to certain foods is bound to eliminate
vital nutrients and vitamins. The plan simply has too few calories to
be safe.
Long-term
Success:
Weight rebound is inevitable.
The
New Beverly Hills Diet
This
1980’s blockbuster encourages the "food combining" or
separating certain foods, theoretically allowing the body to properly
digest each food. A mixture of foods leads to "confused" enzymes,
the author professes. During the initial 35-day diet plan, calories
can range wildly based on the all-you-can eat principle for certain
foods.
Benefits:
The only benefit seen with this strict and sometimes confusing food
plan is its extremely low calorie intake—weight loss is virtually
assured.
Disadvantages:
Science reveals that the digestive tract was designed to handle all
sorts of different food mixtures. While fat can slow the digestive process,
it does hinder the absorption of nutrients. The plan is extremely low
in protein, vitamins and minerals and is likely to cause stomach distress
as a result of large quantities of fruit.
The
New Beverly Hills Diet was created by Judy Mazel.
Neander-Thin
Generically
named the "Caveman Diet," this plan claims that modern processed
and cultivated foods cause obesity. The creators of "paleolithic
nutrition" claim that the caveman was very lean due to his diet,
which consisted of lean meats, fish, fresh vegetables and fruits, nuts
berries and seeds.
Advantages:
The elimination of processed foods means that the dieter consumes more
"whole" foods, which do contain more vitamins and nutrients.
Disadvantages:
To date, there is no scientific research that links carbohydrates such
as wheat and grains to obesity and certain diseases.
Long-term
Success:
Eventual carbohydrate cravings will develop from depleted glycogen stores
and weight rebound is inevitable.
Neander-Thin
was created by Ray Audette.
High-Protein
Diets
Some
of the most frequently asked questions deal with high-protein and fat
diets that brand carbohydrates as evil and as the reason for the prevalence
of obesity in our society today.
Such
diets are not new. They have waxed and waned in popularity over the
years, with the previous crescendo occurring in the '70s. The recent
popularity most likely stems from the fact that, in spite of previous
dietary recommendations and the prevalence of low-fat and non-fat foods,
more and more of the population continues to reach obesity. This increase
in obesity is because people are not following current diet and exercise
recommendations. Let's examine how proponents or marketers of high protein
diets trick their patrons. The following are the most prevalent claims
made in support of these diets:
Claim
1. People are not getting fat from consuming too many calories, but
from the consumption of carbohydrates, especially high glycemic index
(GI) ones.
Despite the claims of these diets, obesity and weight gain are
the result of positive energy balance. If one consumes more calories
than they expend, then there will be an increase in mass. One's genetics
and lifestyle determine how easy it is for this to occur. The problem
is that society's caloric intake has increased (by about 300 calories
in the last decade) and its caloric expenditure has decreased (due
to technology and labor-saving devices).
Glycemic
index refers to the effect on the blood sugar (BS) level of equivalent
amounts of CHO contained in different foods. 6 In other words, how
quickly BS rises and how much insulin is released in response to a
particular food. GI measures a single food source eaten by itself
and on an empty stomach. Several studies have shown that high GI foods
do not have the same glycemic response when given as part of a mixed
meal. Many, if not most, high GI foods eaten today are refined foods,
high in added sugar, and would not be considered wise food choices
by any standard.
We
must still face the truth, which is that high GI foods, while possibly
not the wisest use of calories, are not responsible for weight gain.
People get fat when they consume too many calories in relation to
expenditure.
Claim
2. Carbohydrates stimulate insulin release, causing the body to store
fat. This accompanying insulin production causes insulin resistance
(IR) and the development of obesity and NIDDM (type II diabetes).
It is interesting that none of these diet proponents mention that
protein also stimulates insulin release. Other than genetic IR, most
scientists acknowledge that it is obesity itself (due to an excessive
energy intake) that leads to IR, not the other way around.
Insulin
resistance is often accompanied by several other conditions collectively
known as "Syndrome X." Characterized by insulin resistance, hypertension,
hyperlipidemia and an increased risk of cardiovascular disease, Syndrome
X is usually associated with obesity (especially abdominal), a high-fat
diet and a sedentary lifestyle. A result of these factors is high
levels of circulating free fatty acids (FFA). In the presence of high
FFA concentrations, the body will favor their use as energy, decreasing
glucose oxidation, glycogen synthesis, and inhibiting glucose transport.
The result of this is hyperglycemia. If blood sugar levels are chronically
high, insulin will also be elevated, leading to the conversion of
the excess blood sugar to other products such as sugar proteins, and
fatty acids. These facts alone seem to bolster the idea that carbohydrates
lead to health problems. The truth is that a healthy person would
need to eat an extremely high percentage of simple carbohydrates (sweets),
a high fat diet, be in an energy excess, or overweight to have chronically
elevated blood sugar. The average American eats about 34 percent fat
and less than 50 percent carbohydrate in their diet. The consumption
of mixed meals with these percentages will not allow blood sugar to
be chronically high in a healthy exercising individual. There is some
evidence that diets high in sucrose or fructose and fat can lead to
insulin resistance and obesity in rats. In either case, the solution
is a low-fat diet high in complex carbohydrates. So, how does one
become insulin resistant? If one constantly overeats, excess calories
are stored as fat. Fat cells then increase in size. The growing fat
cell itself becomes insulin resistant and the prevalence of FFA as
mentioned earlier will cause the body to favor the use of fat for
energy, at the expense of glucose. This becomes a viscous cycle that
continues to perpetuate itself. The fatness leads to IR. This leads
to impaired glucose use. BS levels rise. Insulin levels rise. Cholesterol,
TG and blood pressure rise as well. To make matters worse, the impaired
ability of glucose to enter muscle cells keeps glycogen stores lower,
which can increase appetite, motivating the individual to eat more,
increasing fat stores, exacerbating IR, round and round we go.
As
numerous studies point out, high-fat diets are strongly associated
with obesity, thus insulin resistance and diabetes. Of course eating
fat does not make one fat (same with carbohydrate, as explained later)
unless consumed in excess of energy requirements. However, it is easier
to consume excess energy (hyperphagia) on a high-fat diet due to fat's
small volume of food per calorie. Couple the high intake of dietary
fat with excess calories and a sedentary lifestyle and it is easy
to envision an abundance of free fatty acids floating around in the
blood stream. It is much more likely that a high-fat diet leads to
the excess consumption of calories, obesity, insulin resistance and
eventually NIDDM than it is that carbohydrates cause insulin resistance
and, as a result, obesity. The solution, again, is a diet with the
appropriate amount of energy, high in fibrous or starchy carbs, and
exercise. In fact, a study of type II diabetics, people with insulin
resistance and normal weight people found that three weeks of a high-carbohydrate,
low-fat diet and exercise significantly lowered insulin levels.
Claim
3. Low-carbohydrate diets are more effective for weight loss. If
one's goal is simply to lose as much weight as possible without regard
to composition of weight loss, knocking out carbs may be the way to
go. A study comparing short-term weight loss on a ketogenic (very
low CHO and high in fat, leading to ketosis) and nonketogenic diet
illustrate this point quite clearly. Even though total weight loss
was greater on the ketogenic diet, fat loss was essentially equal,
water loss was 177 percent greater (due to decreased muscle glycogen
and muscle water loss), and protein loss was 88 percent greater on
the ketogenic diet. So, for the goal of fat loss, there is no benefit
to the ketogenic diet.
The
disadvantages, however, would likely be a decrease in 24-hour energy
expenditure due to dehydration and loss of lean body mass. Additionally,
for most athletes participating in high-intensity exercise, the decreased
muscle glycogen stores would impair performance significantly and
high-protein diets would decrease testosterone levels when compared
with appropriately mixed food intakes, thus having a negative impact
on recovery. Finally, there is increasing evidence that a high-fat
diet may actually promote body-fat storage in genetically predisposed
obese and post obese individuals.
Claim
4. A ketogenic diet offers a "metabolic advantage".
Dr Atkins, in his book Dr. Atkins' New Diet Revolution, states
that following his ketogenic diet will allow one to lose weight on
a number of calories that once led to weight gain. 26 The state of
ketosis that Atkins seeks can be measured by testing for ketones in
the urine. This leaves us with the knowledge that in the production
and use of ketones for energy, some is excreted (wasted) in the urine.
Essentially, calories are just eliminated. For those interested in
losing fat while gaining muscle, eating a ketogenic, isocaloric diet
sounds very appealing (i.e., eat the calories your body requires but
have some wasted in the urine, creating a calorie deficit and, therefore,
fat loss). However, this excretion of ketones most likely amounts
to only 50 to 60 calories a day, hardly what would be considered a
metabolic advantage. The low glycogen stores that are an inevitable
result of a ketogenic diet would more likely have negative effects
on exercise intensity and appetite, yielding a metabolic disadvantage.
27 Another flaw in the "metabolic advantage" theory is related to
the thermic effect of food (TEF). Thermic effect of food measures
the increase in metabolic rate in response to the ingestion of food.
Studies put this contribution at 5-15 percent of basal metabolic rate
(BMR), when consuming a mixed diet. The low end of the range is seen
in those eating a high fat diet, and the high end is seen in those
eating a high complex-carbohydrate diet. 3 If a person had an absurdly
low BMR of 1000 calories, this would translate into a TEF of 50 calories
on the high fat diet versus a TEF of 150 calories for a high complex
CHO diet. So much for "metabolic advantage".
Missing
the Point
What proponents of low-carbohydrate diets seem to miss is the obvious.
Even though CHO and protein stimulate insulin release and lead to storage
of substrate as FA, it will not lead to long-term fat accumulation unless
caloric intake exceeds caloric expenditure for that day, or week, etc.
These proponents take a complex series of events (human metabolism),
highlight the portion that supports their claim and ignore the big picture.
Because humans are periodic eaters, we will always eat more at a sitting
than can be immediately used for energy. This influx of glucose, amino
acids, glycerol and fatty acids stimulate insulin release so that these
materials can be used for energy and stored for later use (as glycogen
in liver and muscle and fat stores). 5 As an individual goes through
the next several hours without food intake, fatty acids and glucose
are liberated from storage depots to fuel metabolic activity that is
always occurring.
By
the way, in a resting state, fatty acids provide the majority of energy
used, regardless of diet composition. We are storing and liberating
fat continuously throughout the day. There is absolutely no evidence
that a high CHO diet will lead to weight gain if one eats at or below
maintenance. In fact, it is impossible. In the end it is caloric intake
versus expenditure that determines if one increases or decreases fat
stores.
Also,
if one looks at the energy cost of converting macronutrients to fat,
it requires much less energy to convert dietary fat to body fat than
to convert CHO to body fat (5 percent of calories vs. 20-25 percent).
28 A study designed to measure lipoprotein lipase (LPL, a fat storage
enzyme) activity in adipose tissue and skeletal muscle on a high carbohydrate
or high fat diet inadvertently illustrated this. The study design was
to keep participants in calorie balance, so that weight was not gained
or lost. Due to the increased TEF, the participants on the high carbohydrate
diet had to eat approximately 300 calories more to maintain body weight
than the high fat diet group.
Lastly,
one of the biggest concerns associated with high-fat and protein diets,
is the impact on health of the individual. High-protein diets are known
to increase bone-mineral losses (calcium in particular) and tend to
include greater intakes of saturated fats and cholesterol, which contribute
to dyslipidemia. 29,30 Populations that eat diets lower in protein and
fat, and higher in carbohydrates, have the lowest incidences of cardiovascular
disease. It is when a culture adopts a Western diet, high in calories,
fat and sugar and increases their reliance on technology that obesity
and its health problems emerge.
If
the preceding information is not convincing enough that high-protein
diets are not the answer for long-term fat loss in exercising individuals,
consider this: of the 438 initial enrollees of the National Weight Control
Registry (having lost an average of 66.0 lbs. for over five years),
none were successful by following a low-carbohydrate, high-fat diet.
In fact, the common denominator for success dietarily was a low-fat
diet with a macronutrient profile of approximately 20 percent protein,
25 percent fat and 55 percent carbohydrate.
This
information, from a study published in the Journal of the American Dietetic
Association, is the most comprehensive study of its kind to date. Data
from many other studies support this.
Before
concluding, consider these real-world examples: Endurance athletes,
who typically consume between 60-75 percent of their calories from CHO,
are some of the leanest people on the planet. Conversely, Inuit Eskimos,
who consume only protein and fat, comprise the fattest culture in the
world.
A
final thought
Much time and energy is spent searching for the causes of obesity.
Blame is placed on specific foods, classes of macronutrients and genetics.
Adding to the confusion is the erroneous belief that the obese maintain
very high bodyweights despite low caloric intakes. Many studies show
that as body weight increases, reported caloric intake decreases. A
recent study showed that self reported energy intakes in American women
are approximately 750-1000 calories below energy expenditures as calculated
by the doubly labeled water method. This discrepancy increases as body
mass index (BMI) increases. This is more proof that obesity is, at its
most basic level, an issue of energy imbalance. This imbalance perpetuates
itself through a combination of constantly available, palatable food
and a society that promotes a sedentary lifestyle.
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