Introduction :
Obesity as defined by a body mass index above 30 kg/m2is a global health concern that as of 2016 affects 650 million adults
worldwide. The condition is associated with several health consequences,
one of which being an increased risk of cardiovascular disease (WHO,
2020). The obese state is correlated with established risk factors for
cardiovascular disease such as an unhealthy lipid profile , which
include elevated triacylglycerols, total cholesterol, and low-density
lipoprotein cholesterol levels as well as a decreased high-density
lipoprotein cholesterol level. Furthermore, the relationship between
cardiovascular disease and obesity was confirmed in a prospective cohort
study on 5209 participants known as the Framingham Heart Study which
noted that obese participants had an increased age-adjusted relative
risk for cardiovascular disease . A multivariable adjusted relative risk
(adjusted for age, smoking, hypertension, hypercholesterolemia, and
diabetes) in the same study noted that the total cardiovascular disease
relative risk was increased for both obese men and women in comparison
to men and women with a healthy ranged body mass index (18.5 – 24.9
kg/m2). Therefore, as a means to further explore
cardiovascular disease risk as a result of an obese state rather than
cardiovascular disease risk as a result of the co-morbidities associated
with obesity, this systematic review hopes to focus on metabolically
healthy obese adults which include a subgroup of obese adults who do not
exhibit overt cardiometabolic abnormalities such as diabetes, or
hypercholesterolemia . Furthermore, weight loss is associated with a
decrease in the aforementioned lipid levels (Van Gaal, Mertens and
Ballaux, 2005) and therefore obese participants may experience more
balanced lipid profiles when undergoing weight reduction, as through
dietary energy deficits (Strasser, Spreitzer and Haber, 2007). However,
in the context of hypocaloric diets, hunger has been noted as one of the
primary issues in obese participants compliance to weight-loss diets
(LaPorte and Stunkard, 1990). A clinical trial noted that hypocaloric,
high-protein diets significantly lower food cravings, and improve mood
in obese participants (J., E. and G., 2018). This finding concurred with
the observations of several studies which suggested that hypocaloric,
high-protein diets enhance weight loss and increase dietary compliance
as result of increased satiety and decreased hunger (Halton and Hu,
2004; Wycherley et al. , 2012; Leidy et al. , 2015). Adding
to these findings’, studies involving hypocaloric, high-protein diets
also concluded improved lipid profiles (Layman et al. , 2003;
Layman and Baum, 2004). This systematic review therefore hopes to
explore the effects that hypocaloric, high-protein diets have on
cardiovascular risk factors, specifically serum lipid levels and weight
loss in metabolically healthy obese adults, a subgroup of participants
which to current knowledge have not been exclusively explored in regards
to the effects of this specific diet. As suggested from the
aforementioned findings in previous studies it is predicted that
hypocaloric, high-protein diets will produce a significant reduction in
cardiovascular risk factors and an increased weight loss in comparison
to other hypocaloric, non-high-protein diets in metabolically healthy
obese adults.