The Zone Diet Essay Sample

In 1995, Barry Sears published The Zone, a book that depicts a diet developed to reach optimal body function and physical performance (Bosse et al., 2004). The diet is composed of 40% carbohydrates, 30% proteins, and 30% fats, in which one should be restricting their grains and starches and maximizing their fruit and vegetable intake (Zone Labs Staff, 2022). In addition to controlling one’s diet, people should also be taking omega-3 fatty acid and polyphenol supplements. According to Barry Sears, the zone is an actual physiological state that can be measured, and optimal ratios include: less than one for TG/HDL ratio, between 1.5-3 for AA/EPA ratio, and 5% for HbA1c levels. In the zone state, the body is able to control diet-induced inflammation, which prevents weight gain, sickness, and aging (Zone Labs Staff, 2022). Overall though, the diet created ends up being restrictive and hypocaloric. The needs for the diet are calculated based on lean body mass, making the diet ending up to be low in carbohydrates and high in protein intakes (Bosse et al., 2004). 

As stated above, the overall goal of the zone diet is to optimize bodily functions and increase physical performance, essentially improving athletic performance (Bosse et al., 2004). This diet has been marketed towards athletes as a way to increase energy and mental state, which is the state of being in the “zone” (Cheuvront, 1999). According to Barry Sears, the ratios of macronutrients will change the body’s insulin to glucagon ratio, and this alteration will supposedly result in greater and more efficient delivery of oxygen to the muscles (Cheuvront, 1999). With this improvement in oxygen delivery, the muscles do not fatigue as quickly, allowing physical performance to increase. Athletes are able to increase contractions of the muscles, allowing more strength to be used, as well as maintaining higher volumes of work. However, researchers suggest that the zone diet at its core is simply energy restrictive and hypocaloric (Bosse et al., 2004). 

In a study conducted by Bosse et al. (2004), the effects of the  Zone diet were examined for three weeks. The researchers had fifteen participants, eight in the diet group and seven in the control group. The researchers found that the diet had no effect on total cholesterol levels and HDL cholesterol levels, as well as they found a decrease in time to exhaustion on a treadmill run in the diet group. Dansinger et al. (2005) conducted a one year study of a comparison of the Zone diet to several other popular diets. These researchers found a reduction in both HDL and LDL levels for the Zone diet, as well as a reduction in triglyceride levels and diastolic blood pressure. The researchers concluded from the study that it is possible for the diet to help weight loss and reduce cardiovascular risks due to the weight loss, but the diets are shown to be hard to sustain long-term. Dansinger and colleagues found that by month 12 the participants in the Zone diet group only had an average of a level 4 adherence to the diet, which is below the clinically meaningful level of adherence. Overall, these results suggest that the Zone diet is not a substantial diet to maintain long-term, suggesting that any weight loss will likely be put back on after the dieter gives up on the diet. 

Even more so, the Zone diet is essentially a low carbohydrate diet combined with a higher protein diet. Reddy et al. (2002) conducted a study to investigate the effects of such a diet. The researchers had ten healthy participants consume their normal diet for two week, then consume a modified low carbohydrate, high protein diet for two week, and finally, consume a moderate carbohydrate level diet. Ultimately, the researchers found a low carbohydrate diet with a high protein content increases the amount of acid in the body which will affect the kidneys, as the kidneys are responsible for filtration of the blood and balancing the pH levels of the body. Therefore, the increase in acid increases the risk for kidney stones as well as decreases the amount of calcium in the body. Due to the decrease in calcium levels, a person is more likely to experience bone loss as well (Reddy et al., 2002). 

Overall, the Zone diet could potentially have a positive effect on the body short-term, however, the diet is not a substantial option long-term. The diet is restrictive and has potential for damages to the body long-term due to the caloric and carbohydrate restrictions. The cardiovascular improvements are because of the weight loss experienced, but there are healthier ways to go about weight loss that are beneficial for the long-term. The Zone diet also does not improve physical fitness levels, as the diet claims to. However, research about the diet is still quite limited, though it is clear the diet is a fancy low carbohydrate diet, high protein diet. These diets are not ideal for the body, as carbohydrates are the main source of energy, and restriction of this energy source will lead to long-term problems for the body.