As athletes, physicians, sports professionals, and the general public continue to search for the most effective diet for nutrition and physical development, high protein diets have emerged as a viable alternative for many people. However, there are disagreements about how to define a “high protein diet” (Tipton). Touted for many years, the Atkins Diet initially allows no calories from carbohydrates and moves into a maintenance regimen of only meat and vegetables (Westman, Phinney and Volek). The Paleo Diet has emerged as a similar recommendation of organ meats, fruits, vegetables, and nuts while excluding grains, sugar, dairy, and legumes (Tarantino, Citro and Finelli). Considering marketing by dieticians and nutritionists far too numerous to mention, the majority agree that severely limiting or completely eliminating sugar and salt is beneficial to human health. The inclusion of vegetables is also universal. However, the topic of grains, legumes, and flours remain at debate. The thesis of this paper is to present evidence that a Paleo or similar diet is optimum for human health and development.
One definition is that protein intake is more than 16 percent of the total energy intake, greater than the recommended daily allowance, or any intake greater than 35 percent of total energy. For this reason, many nutritionists use protein intake per unit of body weight as a guideline rather than the percentage of total energy. Previous research indicates that the average person should eat between 1.2 and 2.0 grams of protein daily for every kilogram of body weight (Campbell et al.; Lemon; Lemon et al.; Wilson and Wilson). The average American consumes slight less than the recommended daily allowance and this is considered insufficient for people who exercise more than a few hours a week. An appeal with eating a high fat-high protein diet is that there is more a feeling of being satisfied and not hungry (Pesta and Samuel). The mechanisms for weight loss associated with high protein diets are thought to be secretion of the hormones that promote hunger satisfaction, GIP and GLP-1. In addition, the secretion of the hormone ghrelin is decreased which results in an increase in gluconeogenesis, or “fat-burning”, which improves the homeostasis of body glucose levels.
One of the key components to attaining and maintaining successful weight loss goals is to obtain satiety after eating for as long as possible. A person facing constant hunger and feelings of energy deprivation will succumb much sooner to increased and inappropriate intake and an individual who feel satisfied after a meal. The optimum diet plan includes meal satisfaction and levels of basal metabolic rates that create a negative energy balance and subsequent decrease in body fat (Pesta and Samuel). There are a number of factors involved in feeling hunger satiety including the endocrine, gastrointestinal, neural, and cognitive systems. Protein is considered to be the most satisfying macronutrient. Feeling satisfied after eating promotes lower energy intake by overeating or overindulging in carbohydrates. The type of protein ingested has been found to be a factor is satiety, also. A study comparing feelings of hunger reduction found that when whey-, casein-, and soy-protein were compared, there were greater feelings of satiety longer with whey-protein and the other two types (Veldhorst et al.). The difference is attributed to levels of lysine, threonine, leucine, isoleucine, and tyyptophan responses. It is hypothesized that tryptophane breaks down into serotonin, a neurotransmitter, which contributes to feelings of hunger satiety in ingested proteins.
Research is not clear of the effect on body fat gain from overeating protein. While it is known that overeating in general may result in fat mass and body weight increases the type of intake significantly affects the composition of body fat (Claesson et al.), research points to no difference in whether overeating involves carbohydrates or fats in terms of how much fat is stored (Lammert et al.). A study conducted with 30 athletes using resistance training addressed overfeeding protein as defined by per unit of body weight (Antonio et al.). The results reported were that although the study participants consumed 5.5 times more protein than the recommended daily allowance, there was no significant effect on body fat when compared with a control group.
In addition to the type of protein ingested, there appears to important as to whether increasing protein consumption decreases fat and carbohydrate intake (Pesta and Samuel). As in Atkins, Paleo, and other related diets, carbohydrates are obtained only from vegetables and sometimes fruits. When carbohydrates are drastically reduced and protein in increased, amino acids are added to using energy and lipogenesis slows secondary to lower quantities of dietary glucose available (Stepien et al.). The mechanism has the potential to negatively impact the ability of an athlete to exercise at peak levels (Fogelholm). Athletes require adequate supplies of carbohydrates in order to increase strength and endurance. Limiting energy intake and maintaining levels of training for sports purposes require close attention to energy expenditure and changing levels of protein and carbohydrate intake. For obese individuals seeking weight loss for health and appearance reasons, decreasing intake of carbohydrates and increasing protein consumption inhibits the oxidation of fat (Roberts et al.) and lowers the creation of adipose tissue (Pichon et al.).
There are also possible drawbacks to eating a high-protein diet. It may be inappropriate for patients with metabolic diseases since increased intake of branched-chain amino acids may negatively affect the condition (Pesta and Samuel). In addition, high levels of protein in the diet produces increased stress on the kidneys and the high acid load may prove detrimental to patients with renal impairment. Finally, if the goal of a person is to lose weight, exercise may cause excess protein to be changed to sugar in the blood through gluconeogenesis or to ketone bodies; the excess energy produced would slow progress toward weight loss goals.
In conclusion, members of Western civilizations suffer from increasing incidences of type 2 diabetes, fatty liver disease, obesity, and cardiovascular disease negatively impacted by eating diets high in calories, glycemic values, fructose sugar, and high meat and fat components. By examining published evidence, eliminating food that is highly-processed and consuming primarily foods that improve resistance to insulin such as fruits, meat, vegetables, roots, and nuts will reduce the number of people suffering from dyslipidemia, type-2 diabetes, hypertension, and other diet-related diseases. While some individuals who suffer from metabolic diseases such as renal impairment should exercise caution when considering a high-protein diet, research results are leaning toward the option as viable for many people. Well-constructed studies are needed for validation, but while waiting for the results, the average American would be best advised to put down the salt shaker and pick up a celery stick.
Works Cited
Antonio, Jose et al. "The Effects of Consuming a High Protein Diet (4.4 G/Kg/D) On Body
Composition in Resistance-Trained Individuals." Journal of International Social Sports
Nutrition 11.1 (2014): 19. Web. 4 July 2016.
Campbell, Bill et al. "International Society of Sports Nutrition Position Stand: Protein And
Exercise". Journal of International Social Sports Nutrition 4.1 (2007): 8. Web.
Claesson, Anna-Lena et al. "Two Weeks of Overfeeding with Candy, but not Peanuts, Increases
Insulin Levels and Body Weight". Scandinavian Journal of Clinical and Laboratory
Investigation 69.5 (2009): 598-605. Web. 4 July 2016.
Fogelholm, Mikael. "Effects of Bodyweight Reduction on Sports Performance". Sports Medicine
18.4 (1994): 249-267. Web. 4 July 2016.
Lammert, O. et al. "Effects of Isoenergetic Overfeeding of Either Carbohydrate or Fat in Young
Men." British Journal of Nutrition 84 (2000): 233-245. Print.
Lemon, P.W. "Do Athletes Need More Dietary Protein and Amino Acids?". International
Lemon, P.W. et al. "Protein Requirements and Muscle Mass/Strength Changes During Intensive
Training in Novice Bodybuilders."Journal of Applied Physiology 73 (1992): 767-775.
Print.
Pesta, Dominik H and Varman T Samuel. "A High-Protein Diet for Reducing Body Fat:
Mechanisms and Possible Caveats". Nutrition & Metabolism 11.1 (2014): 53. Web. 4
July 2016.
Pichon, L. et al. "A High-Protein, High-Fat, Carbohydrate-Free Diet Reduces Energy Intake,
Hepatic Lipogenesis, and Adiposity in Rats.. Journal of Nutrition 136 (2006): 1256–
1260. Print.
Roberts, R. et al. "Reduced Oxidation of Dietary Fat After a Short Term High-Carbohydrate
Diet." American Journal of Clinical Nutrition (2008): 824–831. Print.
Stepien, Magdalena et al. "Increasing Protein at the Expense of Carbohydrate in the Diet Down-
Regulates Glucose Utilization as Glucose Sparing Effect in Rats". PLoS ONE 6.2 (2011):
e14664. Web. 4 July 2016.
Tarantino, Giovanni, Vincenzo Citro, and Carmine Finelli. "Hype or Reality: Should Patients
With Metabolic Syndrome-Related NAFLD be on the Hunter-Gatherer (Paleo) Diet to
Decrease Morbidity?" Journal of Gastrointestinal and Liver Diseases 24.3 (2015): n.
pag. Web. 4 July 2016.
Tipton, Kevin D. "Efficacy and Consequences of Very-High-Protein Diets for Athletes And
Exercisers". Proceedings of the Nutrition Society 70.02 (2011): 205-214. Web. 4 July
2016.
Veldhorst, M. et al. "Protein-Induced Satiety: Effects and Mechanisms of Different Proteins".
Physiology & Behavior 94.2 (2008): 300-307. Web. 4 July 2016.
Westman, Eric C, Stephen D Phinney, and Jeff Volek. The New Atkins for a New You. New
York: Fireside Book, 2010. Print.
Wilson, Jacob and Gabriel J Wilson. "Contemporary Issues in Protein Requirements and
Consumption for Resistance Trained Athletes". Journal of International Social Sports
Nutrition 3.1 (2006): 7. Web. 4 July 2016.
