A low-glycemic diet is based on the principles of the glycemic response and glycemic index of foods in nutritional science. Different foods are classified by glycemic index which is the rate of glycemic response that they elicit. Glycemic response is an indicator of how much glucose is released during food consumption and how quickly glucose is absorbed after eating, returning to normal. For health purposes, it is desirable that the return to normal glucose levels is smooth (low glycemic response). Glycemic-based food selection is controversial as the information and index is not strongly supported by research nor can an individual easily determine the glycemic index of a food. However, most nutritional guidelines to healthy eating such as spreading out small meals and consumption of more whole grains, legumes, vegetables, and dairy are beneficial to maintaining a low-glycemic response in the body (Rofles et al., 2014).
Research surrounding low-glycemic diets for weight loss yield inconsistent results, however a high glycemic diet will likely result in weight gain. Low-glycemic diets have the secondary effects of curbing appetite and limiting energy intake as well as being rich in nutrient and fibers. Combined these factors will contribute to weight loss, particularly in overweight individuals as low-glycemic diets are lower in calories, but there is no evidence that this diet is more effective than others such as low-fat, portion-controlled diet targeted at weight loss (Rofles et al., 2014).
Low-glycemic foods can curb spikes in blood glucose, insulin response and glucagon inhibition. However, these foods commonly have high amounts of fiber which prolong distention of the GI tract, secretion of cholecystokinin and incretin, and extending satiety. A meta-analysis of 19 randomized trials for overweight individuals following a low-glycemic diet did not show weight loss in comparison to the control isocaloric diet. However, glycemic control had a prevalent effect on patient’s HbA1c levels over a 6-month period as demonstrated by another meta-analysis of 11 studies (Sandouk & Lansang, 2017). Therefore, based on this information, it can be said with confidence that a low-glycemic diet is not the ideal approach to weight loss. It has a variety of positive health effects that may or may not lead to minor weight loss, but it is not a diet targeted specifically for the purpose, but rather towards those experiencing issues with high blood sugar and insulin resistance such as individuals with diabetes in any form.
The no-fat diet
The no-fat diet (or rather ultra-low-fat diet as it is virtually impossible to not consume any fats) is a variation of the highly promoted low-fat diet that has been proven to be ineffective in long-term weight reduction. Proponents of ultra-low-fat diets argue that low fat is not enough and suggest reducing caloric intake from fat to as low as 10%. However, such a miniscule fat amount in the diet is not healthy in the long-term along with being unsustainable. Naturally, the reduced fat may be linked to reduced instances of blood pressure and have positive effects on heart disease and diabetes. This type of diet results in limits on intake of highly healthy foods that contribute to providing nutrients and vitamins that cannot be found in other foods (Palsdottir, 2019).
Various highly critical fat-based lipids are necessary for body function. Lipids help to maintain homeostasis, protect against shock, and maintain cell membranes. Triglycerides which come from fat in food or body fat stores, are vital to energy production. Meanwhile, the body also requires essential fatty acids, two of which Omega-3 and Omega-6 cannot be made within the body and must come from diet. It is important to note that the no fat diet is essentially comes from a misconception that all fat is harmful to the body which is not the case. It is solid fat such as saturated and trans fats that are negative from the body, and often come from highly unhealthy foods in the American diet such as fatty meats, pizza, and desserts. Meanwhile, monounsaturated and polyunsaturated fats are necessary for the body and offer health benefits if taken in healthy amounts, stemming from foods such as seafood, nuts, and vegetable oils (Rofles et al., 2014).
In conclusion, a no fat diet is both unhealthy and is not based on evidence. However, a diet which eliminates solid fats and focuses on partaking healthy fatty acids is beneficial for a healthy lifestyle. Partaking healthy fats reduces LDL cholesterol and lowers risks of heart disease, diabetes, and other conditions. A healthy range of energy intake from fat is 20 to 35% with minimized intake of saturated and trans fats (Rofles et al., 2014). Most people following the American diet and lifestyle will likely benefit from cutting back fats but removing it altogether is both ineffective and unsustainable for health and diet.
Protein supplements
Protein supplements are a popular product often marketed as a necessary product to stimulate muscle growth. However, based on evidence, the statement that “Protein supplements are an athlete’s ‘best friend’!” is incorrect. Athletes often consumer protein powders with the hope that the amino acids will contribute to muscle growth. First, the supplement itself cannot build muscle on its own, it requires muscle work via progressive overload. Muscle growth occurs via protein synthesis with amino acids derived from foods. Protein supplements can help to slightly increase protein synthesis, but they are neither a replacement for actual food nor would ingesting additional protein anyhow contribute to additional muscle growth beyond what has been achieved through natural workouts. Protein supplements have not been proven to increase athletic performance, and remain nothing more than a supplement to support healthy protein foods required to build lean muscle mass (Rofles et al., 2014).
Protein is ubiquitously present in most diets, coming from animal sources such as fish, meat, eggs, and dairy, as well as some plant sources such as legumes. Undoubtedly athletes require greater protein consumption than an average human due to raw energy spending in sorts and the necessary materials needed to build and repair muscle and connective tissue that are under constant stress in sport. During periods of frequent high-intensive exercise in training or competition as well as potential situations where appropriate meals are not available (i.e. during travel), protein supplements may be viable in maintaining function and energy production. Certain essential amino acids are difficult to acquire from food alone, and to meet these nutritional requirements, supplements such as branched-chained amino acids (BCAA) have been created. Protein supplements have been associated with reduced muscle soreness and brain neurotransmitter production that reduce fatigue development. Nevertheless, studies show that this supplementation applies mostly to elite athletes who have highly developed and strong organisms and require additional aid for function in intense sporting events. For regular gymgoers and recreational athletes, protein supplements are not necessary, and a healthy diet will be able to provide the necessary protein needs for the body (Kårlund et al., 2019).
References
Kårlund, A., Gómez-Gallego, C., Turpeinen, A. M., Palo-Oja, O. M., El-Nezami, H., & Kolehmainen, M. (2019). Protein supplements and their relation with nutrition, microbiota composition and health: Is more protein always better for sportspeople? Nutrients, 11(4), 829. Web.
Rofles, S. R., Pinna, K., & Whitney, E. (2014). Understanding normal and clinical nutrition (10th ed.). Cengage Learning.