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.