Caroline Pelley
NUTR 417 Essay 2
Effects of Low Carbohydrate Diet on Healthy Individuals
As obesity rates continue to increase in prevalence in the United States, more individuals
begin to contemplate the optimal diet for health (Bravata et al, 2003). Low carbohydrate diets
continue to come in and out of popularity, from Adkins to Paleolithic diets (Bravata et al, 2003).
Their popularity stems from links to rapid weight loss, but low carbohydrate diets are also
suggested to be beneficial to healthy individuals (Bravata et al, 2003). In contrast, both the
American Dietetics Association (ADA) and the American Heart Association (AHA) warn
against low carbohydrate diets. There is both support and criticism for the Acceptable
Macronutrient Distribution Range of 45-65 % of daily calories from carbohydrates and the
minimum of 130 grams of carbohydrates per day. The remaining essay will discuss the potential
benefits and detrimental effects of a low carb or high protein and fat diet.
Total antioxidant capacity (TAC) was tested in healthy individuals on low carbohydrate
diets, and the researchers found that higher TAC was seen in subjects with lower daily intake of
carbohydrates; although this could not be separated for total calorie intake (Barbosa et al, 2014).
A higher TAC is associated with reduced inflammation and oxidative stress which would be
beneficial to a healthy individual if proven (Barbosa et al, 2014). In the randomized control trial,
three healthful diets were compared in their ability to reduce blood pressure and serum lipids
(Appel et al, 2005). The substitution of carbohydrates with plant-based protein sources was
shown to lower blood pressure, LDL cholesterol, and triglyceride levels. When unsaturated fat,
mostly mono-saturated, was substituted for carbohydrate blood pressure and triglyceride levels
decreased and HDL levels increased (Appel et al, 2005). The lowering of blood pressure and
triglyceride levels reduces risk for cardiovascular disease, which would be beneficial to a healthy
individual (Appel et al, 2005). A second randomized trial supports the decrease in VLDL
particles and triglycerides: an increase in HDL particles was seen in a diet with low
carbohydrates when compared to a conventional diet (Seshadri et al, 2004). This shift in particles
reflected reduced risk of coronary atherosclerosis and myocardial infraction, at least among
obese individuals (Seshadri et al, 2004). This study also noticed a decrease in C-reactive protein
levels, which may indicate that low carbohydrate diets decrease inflammation (Seshadri et al,
2004). Since this was not the objective of the trial it should be replicated to support the claim
(Seshadri et al, 2004). In other studies, opposite results were produced in risk for cardiovascular
disease.
In a prospective cohort study, low carbohydrate diets were associated with increased risk
for cardiovascular disease (Lagiou et al, 2012). Unlike the previous studies, this one did not
make considerations for the types of carbohydrates and the sources of protein (Lagiou et al,
2012). The replacement of carbohydrates with fat is known to increase triglyceride levels, a risk
factor for cardiovascular disease (Appel et al, 2005). In another study, researchers found that an
increased protein intake (aimed at replacing carbohydrates) may lead to increased acid and
calcium excretion, two factors tied to greater risk of kidney stones and bone loss (Reddy et al,
2002). The potential for effects on cognition and mood were examined in the next article (D’Anci
et al, 2009). Individuals on low carbohydrate diets were shown to have decreased memory in
cognitive tasks. In a second cohort study, a low carbohydrate diet was associated with the
greatest detrimental effect: increased mortality if pursued long-term (Trichopoulou et al, 2006).
In conclusion, there may not be enough evidence to support the recommendation of a low
carbohydrate diet (Bravata et al, 2003). While there appears to be benefits for healthy individuals
who pursue low carbohydrate diets, there were confounding factors. In one study, benefits were
only seen when specific fats or protein were replacing the carbohydrate consumption (Appel et
al, 2005). In another, carbohydrates could not be separated from total calories when associating
the benefits to TAC (Barbosa et al, 2014). It appears a low calorie diet with plant-based protein
and unsaturated fats may be a recommended diet, but more support is needed. The articles
critiquing the low carbohydrate diet had other flaws: one did not distinguish between subtypes of
macronutrients consumed (Lagiou et al, 2012). Furthermore, none of the articles really defined
what a low carbohydrate diet is. Based on these findings, it is best for a healthy individual to
consume a balanced diet of whole grains, both plant and animal based proteins, and many fruits
and vegetables. Whether the percentages of carbohydrates lines up with the distribution ranges
for macronutrients does not appear to lean more towards benefits or detrimental effects.
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