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Running head: ARE WE REALLY WHAT WE EAT?
Are We Really What We Eat?: The Importance of Macronutrient Composition in Diet
Rebecca Collins
Dixie State College
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Abstract
Many people are concerned with losing weight or improving their health, and with good reason.
Obesity is predicted to become the leading cause of death and can increase a person’s risk for
many kinds of fatal health complications. When trying to lose weight, many wonder what sort of
diet is the most successful for weight loss or which is the healthiest diet for the body. Lowcarbohydrate diets are popular, but cannot be recommended because the weight loss that results
is rarely maintained. High-protein diets have shown greater success for long-term weight loss,
due to the thermogenic effect of this macronutrient, which results in a higher metabolism and
prolonged feelings of fullness. Fats have been shown to have positive effects on the diet, and
which fats are consumed can seriously impact weight loss and maintenance. However, though
the food we choose to eat has a significant impact on our health, weight loss is not dependent on
what we eat, but rather how much we eat—however, what we eat has a direct effect on how
much we eat. The importance of physical activity and a regular sleeping schedule are also
important factors when attempting weight loss. Individuals will gather that “dieting” is not an
efficient approach to weight loss, and understand the importance of implementing subtle
behavioral changes over time to maximize weight loss efforts and adopt a long-lasting healthy
lifestyle.
Keywords: macronutrients, weight loss, weight maintenance, physical health, nutrition,
diet, lifestyle, obesity
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Are We Really What We Eat?
You are what you eat—this is classic proverb common to our society has become quite
the cliché throughout the years. But could it really be the truth? Many people concerned with
weight loss wonder about this question; does it really matter what you eat when losing weight, or
does it only matter how much? Many people know to lose weight they must restrict the number
of calories they are consuming, but if a person eats a certain caloric number of apples and bread
or the caloric number of chicken breasts and spinach, will the weight loss reflect what was eaten,
even if the caloric number between diets was consistent? There seems to be a lot of hullabaloo
about this topic; someone always has a shocking new answer, advocating some diet sure to drop
pounds fast. One day a low-carb and high-protein regime is the sure way to go, while the next
someone is advocating a diet focused on average-protein and high-fat. Does the composition of
our diet significantly affect our weight loss? The answer that I have found is that yes it does; but
at the same time, no it does not.
In my experience, every diet has an equal and opposite binge; if I am good and eat a
specifically controlled sort of diet for a short amount of time, I tend to be moderately successful
for just long enough to realize how much I miss my old eating habits, which then results in a
relapse in which I overcompensate for missing those foods, finding myself back at square one
quicker than ever. This tends to be the way of most dieters, and this system of resolving to follow
fad diets so often followed by quick lash backs can’t be helpful to our diet—in fact, I believe it
can even be harmful and detrimental to a person’s actual weight loss goals. The problem with a
“diet” is that a diet will end, and some six-month made-over eating regime can’t miraculously
change the eating habits that a person has established throughout a lifetime. Working towards
healthy lifestyle is a much more productive goal than adopting the latest trendy diets.
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Why Diet Matters
While the macronutrient ratio of our diet (the three macronutrients being carbohydrates,
protein, and fats) may have been shown not to significantly affect weight loss in a fixed-calorie
setting, ad libitum studies have proven that what we eat has a direct influence on how satisfied
we are with our diet, which affects how much we eat. For this reason, weight loss is incredibly
difficult to achieve without altering the composition of the macronutrients in our diet.
Schusdziarra et al. (2011) points out in one study that behavioral interventions have been proven
to be one of the most if not the very most important factors for successful weight loss. Since
different macronutrient ratios of our diet affect our behavior and thus our total energy (calorie)
intake and satiety or fullness, one can see that while the macronutrient composition may not
directly influence weight loss, modification of the ratio in some way is of the utmost importance
in achieving weight loss.
While this information may seem to be important only to those interested in losing
weight, the macronutrient composition of a person’s diet also affects not only his or her internal
health, but also his or her ability to maintain a healthy weight. This is an issue that everyone
needs to be aware of, due to the rapidly rising issue of worldwide obesity. Obesity is defined as
having a BMI (body mass index) of 30 or over, and obesity increases the chances of developing
all sorts of life-threatening complications such as cardiovascular disease, hypertension, and even
certain cancers (MacDonald, 2005). In fact, McLaughlin et al. (2006) even mentions that obesity
is projected to be the leading cause of death in the United States if something does not change.
Even if we are not at risk due to obesity, chances are that someone we know and love is at in
danger of developing weight-related health problems. Thus, it is extremely important to be aware
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of the effect the foods we eat may be having on our bodies and increase efforts to manage weight
on a long-term scale.
Even more alarmingly, even our genes are being affected by our diet and lifestyle. Bray
(2008) mentions this in his review of Taubes’ book Good Calories, Bad Calories, writing that
“some factor of diet and/or lifestyle must be driving weight upward, because human biology and
our underlying genetic code cannot change in such a short time.” (p. 253). Though the urgency
of weight loss has been a prevalent issue for several centuries, over the past few decades our
lifestyle has changed drastically to include less day-to-day activity and a higher consumption of
highly processed foods. MacDonald (2005) submits that we no longer are in tune with our bodies
and don’t know what they need, and we often turn to the cheap convenience of junk food rater
than choosing fresh fruits and vegetables or lean proteins and whole grains. This simply is not
having a positive effect on our health and, evidently, even our genome.
Katz (2010) even goes so far as to point out that on the cellular level, we really are what
we eat, since the composition of our blood, hormones, bone marrow, and even cell membranes
are all determined by the nutritional content of our food. Thinking of it this way, our bodies
literally are made out of the food that we eat, and therefore our bodies will only be as clean and
healthy as the food that we put into them (Katz, 2010).
The Big Three Building Blocks
Carbohydrates
There are three macronutrients that make up every diet, as previously mentioned:
carbohydrates, fats, and proteins. When most people try to diet, they typically will turn to the
popular approach of committing to a low-carbohydrate diet with high-protein; many studies have
explored this type of diet, however, and while success has been achieved in the short-term,
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follow ups have often shown that low-carbohydrate diets are not successful in sustaining weight
loss. In a study done by van Baak and Astrup (2009) exploring the effect of sugars on weight
loss, the carbohydrate content of a diet was actually found to be relatively benign, with little
evidence found for dietary sugar having directly negative effects on body weight—instead, van
Baak and Astrup (2009) submit that “the ratio of other macronutrients in the diet may be more
important.” (p. 10).
In spite of this, carbohydrates can be ignored. In van Baak and Astrup’s (2009) same
study, different sugars were in fact shown to have different effects on the body. While we all
know that drinking sugar- and high fructose corn syrup-sweetened beverages has a detrimental
effect on our health, we may be underestimating the extent to which we are sabotaging ourselves
when consuming sugar in liquid form. The habit of drinking one or more soft drink per day was
shown to result in higher likeliness of obesity as well as increased waist circumference when
compared to a control group who consumed the same amount of sugar in a solid form, by way of
jelly beans (van Baak & Astrup, 2009). In both cases, the increased sugar intake also tended to
replace regular intake of fat and protein as well, which proves another way that sugar—
regardless of whether it is liquid or solid—is negatively affecting our diet.
The replacement of other macronutrients with sugar carbohydrates could also be a result
of the way sugar tends to spur consumption of more sugar. For example, think of how much
easier it is to be satisfied after eating a small amount of raw almonds as opposed to how easy it is
to achieve satiety eating a small amount of honey-roasted almonds; that sugary coating often
drives a person to eat more (Katz, 2010). Processed foods are often full of these kinds of refined
sugars, which result in flavoring that can overly stimulate the hypothalamus, or the appetite
center of our body. This effect results in unintentional consumption of greater amounts of low-
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fiber carbohydrates (sugars rather than whole grains, for instance), which leads to eating food
with a high ratio of calories to nutrients and consequently an overall higher caloric intake (Katz,
2010).
Therefore, while it is futile to sustain a low-carbohydrate diet (Sacks et al., 2009) and
low-carbohydrate diets cannot be recommended (van Baak & Astrup, 2009), it is important to be
wary of how many carbohydrates we are consuming and the quality of those carbohydrates. It
doesn’t take too much common sense to realize that eating carbohydrates in the form of an apple
(natural sugars) is a wiser choice than eating a candy bar (refined sugars). Natural sugars also
tend to be present in foods with a higher content of fiber and water, which fills up the stomach
more and increases feelings of satiety, resulting in feelings of greater satisfaction and a lower
energy intake overall.
Proteins
Protein is another highly-advocated macronutrient in the weight loss circuit, with high
protein regimes showing a little higher success rate than low-carbohydrate diets in the long run,
with sustainable long-term weight loss (van Baak & Astrup, 2009). In a study conducted by Due,
Toubro, Skov, and Astrup (2004) in which the effects of medium-protein and high-protein diets
were compared in relation with weight loss, the high-protein group was shown to not only lose
3.5 kg more weight, but also had a greater reduction in waist circumference. These findings
suggest that a high intake of protein might influence the distribution of fat and result in a
reduction of abdominal fat. Due et al. (2004) hypothesized that this indicates a correlation
between consumption of protein and reduction of cortisol, a hormone caused by stress that
causes excess abdominal fat, but that is a question for later studies.
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Another reason that increased protein has been proven to be so successful in weight loss
is the thermogenic effect of this particular macronutrient. The thermogenic effect is known as the
way that foods can increase the amount of heat the body creates in digesting them, resulting in a
heightened metabolic rate for a short amount of time. Protein has the highest thermogenic effect
of all the macronutrients—27% of the calories of pure protein a person consumes will be used in
digesting this macronutrient (Due et al., 2004). This means that not only will metabolism be
quickened by consumption of protein, but because protein is difficult to digest, it will stay in the
stomach longer resulting in greater feelings of satiety and fullness. All of these things contribute
to an overall lower energy intake, which in turn leads to more successful weight loss.
Eating more protein has also been associated with eating less of the other two
macronutrients: fats and carbohydrates. Due to the aforementioned thermogenic effect of protein,
eating high protein generally replaces calories otherwise spent on less filling foods, resulting in
eating less. One study reports that intentionally replacing fats with proteins resulted in more
pronounced weight loss among participants (McLaughlin et al., 2006) and another review of
studies found that the influence of higher protein intake on lower intakes of other macronutrients
resulted in significantly higher, better-maintained weight loss in the long-term (van Baak &
Astrup, 2009). Thus, increasing the protein intake in one’s diet can result in greater long-term
weight loss and weight management, because protein increases feelings of fullness which leads
to decreased total caloric intake.
Fats
The last macronutrient, fat, has a universally bad reputation. However, this macronutrient
is an important part of our diet. Just as we should avoid choosing refined sugars over whole
grains when consuming carbohydrates, fats are not created equal. Polyunsaturated and
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monounsaturated fats can actually result in a subtle reduction of abdominal fat (Sacks et al.,
2009), while inversely, trans fats and excessive amounts of saturated fat have been known to
dramatically increase the amount of visceral (abdominal) fat in the body. Schusdziarra et al.
(2011) points out that fats have a higher energy density, meaning they have a lower satiating
capacity than other macronutrients. In van Baak and Astrup’s (2009) review of sugars and body
weight, the fat content of a diet was also shown to be “the most important contributor to passive
over-consumption” (p. 9), suggesting that eating fatty foods tends to spur the appetite to crave
fatty foods and result in the consumption of more high-calorie foods and consequently greater
calories overall, much like sugary foods. Therefore, while healthy fats have been advocated as
important element of a healthy diet and have their time and place, the fat content of a diet still
ought to be monitored and caution must be taken to ensure that the majority of fats being
consumed are the healthier unsaturated fats.
Dealing with Diets
While many people are aware that they ought to lose weight or improve their health, all
too often a person will jump to commit to the first diet that catches his or her eye in hopes to
drop pounds fast. However, this is the complete wrong approach to take if the dieter wishes to
keep off the pounds they do drop. Dieting has been proven time and time again to be an
ineffective approach to weight loss. Due et al. (2004) brings up the fact that although many diets
tend to show success in short amounts of time, maintaining that weight loss proves to be a very
difficult and persistent problem. Most diets result in fast weight loss within the first six months
followed by a steady regain of the lost weight throughout the consecutive year. This occurs
because while a diet may initially work to achieve weight loss, all “diets” eventually end—and
when the diet ends, the weight comes right back. Thus, striving to understand how to make
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subtle dietary changes to contribute to a healthier lifestyle is a more effective way to approach
weight loss than adopting short-term eating style that has strict macronutrient composition and
calorie limits.
Sacks et al. (2009) supports this idea, saying in his study of macronutrient composition
that behavioral factors as opposed to a diet’s macronutrient makeup are the main factors
influencing weight loss. However, upon studying each of the three macronutrients, I submit that
which macronutrients we choose to consume have a powerful influence on our behavior and in
fact are their own behavioral factor. Therefore, making little alterations in our day-to-day diets
can eventually alter behavior enough to directly result in gradual, healthy weight loss and
success in weight maintenance. Schusdziarra et al. (2011) points out that such dietary changes
have to be appealing not just for months or weeks, but for years—meaning that crash dieting is
doomed to fail in the long run. This is supported also by McLaughlin et al. (2006), who observed
that the closer a diet program is to the usual dietary patterns of a patient, the more successful the
patient will be in adhering to the diet. After all, Bray (2008) also notes that weight loss is related
more to the actual adherence to a diet rather than relating to what the diet is. Thus, we must
realize the importance of being aware of how certain macronutrients are affecting our bodies and
make lifestyle adjustments accordingly to fit specific weight loss or management goals.
The Influence of Exercise and Sleep
Exercise
In consideration of changing behavior and lifestyle, the question of physical activity is
unavoidable. Many people believe that simply by dieting and ignoring the idea of exercise they
can lose weight—and while this may be true, working out regularly makes the process faster and
easier. In my own experience, I find myself naturally eating healthiest when I am taking time to
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exercise regularly. On the other hand, when I find myself particularly busy and without time to
work out, I crave foods high in bad fats and sugars. Food is fuel, and when we are exercising
often our body will feel that and it is easier to eat for fuel and less tempting simply to eat for
pleasure. Keeping up with a regular cardio regime can really make a difference in the type of
foods that the body naturally craves, and consequently a person might find themself reaching for
a banana over a cookie impulsively.
Many people believe that a bad diet can be countered with exercise, and live strictly on a
calories in/calories out philosophy. However, though there is some truth to the idea that a calorie
deficit will result in weight loss, and though a calorie deficit can be achieved through exercise,
diet matters. Once again, food is fuel, and if we are not fueling our bodies correctly, the activity
that we are doing is likely to suffer from those poor choices. The facts that protein builds
muscles and carbohydrates provide energy are common knowledge, and the quality of the protein
and carbohydrates consumed can have a rather large influence on how we feel and how long we
can continue in a workout. Poor food choices yield poor performance in exercise, and good food
choices yield strong performance in exercise—it’s just that simple.
Sleep
Another factor that cannot be ignored is that of sleep. It has often been sad that while a
person cannot out-exercise a bad diet, it is even more ridiculous to try to out-exercise or out-diet
lack of sleep. Sleep is an important biological process wherein our body recharges and sort of
resets for the next day. Lack of sleep can wreak all sorts of havoc on the body, as deprivation
often upsets the body’s natural balance of hormones. It is no secret that a lack of sleep can
heighten stress levels—this can result directly in more visceral fat, hard-to-lose fat that
concentrates in the abdominal area specifically, due to a hormone called cortisol. Besides, that,
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lack of sleep also causes imbalance in other hormone levels. Levels of ghrelin, a hormone that
stimulates appetite, have been found to rise when the body hasn’t slept enough. Levels of the
hormone leptin inversely plummet, which can cause lesser feelings of satisfaction when food has
been consumed. Thus, lack of sleep can make the struggle with controlling energy intake much
more difficult.
Sleep also affects diet in other ways; when a person has had more sleep, he or she tends
to make more healthful decisions about food to eat. When tired, people tend to grab highlyprocessed on-the-go foods as opposed to more healthful, thought-out meals, which often means
low nutritional content and too many refined sugars. This, as mentioned above, works to spur
eating more which leads all-too-easily to weight gain. The importance of both sleep and diet
cannot be underestimated when striving to make healthy food choices and lose weight.
What We Should Do
When it comes to diet, while the specific macronutrient composition of diet may not have
a direct effect on the rate of weight loss, the various components and influences of each
macronutrient certainly affects overall energy intake and can have a profound effect on our
internal health as well. However, strictly from a controlled calorie setting, “changes in the
composition of the diet have little or no influence on weight loss on individuals given a fixed
energy intake” (Bray, 2008, p. 259). Nevertheless, literally speaking, we are what we eat, and we
ought to be conscious that we are feeding our bodies quality foods to ensure a healthy lifestyle.
Making an effort to increase protein consumption can indirectly replace the amount of lesssatiating fats and carbohydrates, resulting in greater long-term sustainable weight loss and a
healthier diet overall. As long as we are implementing small, subtle dietary improvements and
staying active, weight loss doesn’t mean crash dieting or drastically changing the macronutrient
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composition of the diet; just making choices every day for a healthier lifestyle that we can
maintain throughout our lives.
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References
van Baak, M. A., & Astrup, A. (2009). Consumption of sugars and body weight. Obesity
Reviews, 10(Suppl. 1), 9-23. doi: 10.1111/j.1467-789X.2008.00561.x
Bray, G. A. (2008). Good calories, bad calories. Obesity Reviews, 9(3), 251-263. doi:
10.1111/j.1467-789X.2008.00476.x
Due, A., Toubro, S., Skov, A. R., & Astrup, A. (2004). Effect of normal-fat diets, either medium
or high in protein, on body weight in overweight subjects: A randomised 1-year trial.
International Journal of Obesity & Related Metabolic Disorders, 28(10), 1283-1290. doi:
10.1038/sj.ijo.0802767
Katz, D. (2010). The case for natural foods. Prevention, 62(3), 124-127.
MacDonald, P. (2005). The obesity crisis…it's not just about diets. Practice Nurse, 29(8), 17-21.
McLaughlin, T., Carter, S., Lamendola, C., Abbasi, F., Yee, G., Schaaf, P., . . . Reaven, G.
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Sacks, F. M., Bray, G. A., Carey, V. J., Smith, S. R., Ryan, D. H., Anton, S. D., . . . Williamson,
D. A. (2009). Comparison of weight-loss diets with different compositions of fat, protein,
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Schusdziarra, V., Hausmann, M., Wiedemann, C., Hess, J., Barth, C., Wagenpfeil, S., &
Erdmann, J. (2011). Successful weight loss and maintenance in everyday clinical
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