The effects of high protein consumption in relation to weight loss and muscle mass

Introduction:

One of the effects while dieting is the loss of muscle mass. For some people, this can have adverse consequences and is recommended to combine exercises to reduce this loss. However, according to Leidy, Carnell, Mattes, & Campbell (2007), there is not a successful diet treatment to lose weight, despite, diets centred in High-Protein (HP) are a common method for this purpose.

However, some researches state that an HP diet, compared to the normal-protein (NP) restricted diet, have better results regarding the loss of body weight, conservation of lean body mass (LBM) and losing fat mass (Leidy et al., 2007).

Some of the causes for these positive results mentioned by Leidy et al. (2007) are stimulated for the increase of heat through metabolic stimulation, due to HP meals,  contribution to reducing the apparent appetite, less need to eat and lasting longer the satiety factor.

This article will overview the effects of HP consumption in relation to weight loss and muscle mass. The document will examine the advantages and disadvantages of the HP diet and recommendations while dieting with HP meals as those with low saturated fat and considering any specifically targeted subjects.

High-Protein (HP) diets:

Weight-loss programs for adults promoting HP intakes recommend 1.5g of protein per kg of body weight through energy deficit (ED) diets to reduce the loss of fat-free mass (FFM), while the normal recommended dietary allowance (RDA) of protein is 0.8g per kg of body weight (Pasiakos et al., 2013). See below Figure 1.

According to Layman (2004) cited in a recent research (Campos-Nonato, Hernandez and Barquera, 2017), diets including high-quality (amino acid composition)  protein (HQP) in combination with  lower intakes of carbohydrates are  successful to lose weight, furthermore Layman (2004) suggested that those programs stimulate a metabolic benefit, while the diet is in place, producing a major loss of body fat and the same time decreasing the loss of  lean tissue and easing the blood glucose system.

More High-Protein (HP) diets:

Also, Layman (2004) proposed that amino acid leucine is responsible for this metabolic effect of HP diet due to it’s the exclusive functions regulating the synthesis of muscle protein. Additionally, Layman recommends consuming HQP at breakfast for a better metabolic benefit.

Another study (Cuenca-Sánchez, Orenes-Piñero and Navas-Carrillo, 2015) regarding HP diet has concentrated their research on long-term HP diet, apparently, they are responsible for clinical problems such as renal malfunction and losing the mass of bones. However, Cuenca-Sánchez, Orenes-Piñero and Navas-Carrillo (2015) stated in their research that there is not much evidence that HP diets are unsafe for healthy individuals, defined by the World Health Organisation (2006) as “a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity.”

As Layman (2004) and Campos-Nonato, Hernandez and Barquera (2017), Cuenca-Sánchez, Orenes-Piñero and Navas-Carrillo ( 2015) also found in their research that HP meals have better satisfying effect, feeling full after eating, than high carbohydrate (HC) or high fat (HF) meals, the  protein also send information to the brain by metabolic hormones regarding energy levels, producing in a long term effect the reduction of food consumption.

Protein in meals through the day:

Another research regarding protein intake in adults (Loenneke et al., 2016) concentrates their research on the benefits of the distribution of the protein in meals through the day. The RDA recommends the daily amount of protein in a day, however, the RDA fails to clarify the amount of protein a person should intake in each meal, so Loenneke et al. (2016) based their study if increasing 30g of protein has any benefit related to lean mass and knee extensor strength.

The outcomes showed that people taking part of their study, consuming between 30 and 45g protein in the meal gain lean mass and strength and recommend considering the intakes of 1-2 daily meals with HP to maintain this lean body mass and muscle strength with elderly people.

Contemplating elderly people, Symons et al. (2009) stated in their article than the consumption of HP is vital for muscle protein synthesis (MPS) and preservation of lean muscle mass. As well, Symons et al. (2009) explained that ageing people have more probability of protein malnutrition and develop sarcopenia muscle loss.

Others researches (Astrup, 2005; Astrup et al., 2008) also suggested that an increase of protein intake over the RDA may improve the synthesis of muscle metabolism, enlarge satiety, increase body heat and the amount of energy a person expends.

Advantages of HP diets:

The main advantages of an HP diet exposed in this document may be resume by similar findings  exposed by Astrup et al. (2008),  they resumed these benefits as:

1.- The satiety effect: HP meals rise the feeling of fullness even more than carbohydrate or fat meals and perhaps help to a decreasing energy intake while dieting.

2.- Raise body temperature: HP diets are related to thermogenesis, so the amount of energy expended is greater and additionally impacts satiety too.

 3) The increase of fat-free mass:  The muscle protein constructive metabolism can be affected by an HP diet, facilitating the maintenance of lean muscle mass. Still, any possible benefits must be assessed with individual and usual dietary practices.

Disadvantages of HP diets:

Renal Function

One of the adverse effects of an HP diet considered on Halton and Hu (2004) article is the safety of the kidney function regards these diet. However, Halton and Hu (2004) emphasised the distinction between healthy people and one with renal problems, additionally reinforcing their recommendation over vulnerable people, e.g. with diabetes, and suggested higher attention with HP consumptions. In more recent research (Friedman et al., 2012) similar results were obtained, HP diets were not related with appreciable hurtful consequences.

Blood Lipids and Cardiovascular Disease Risk

Another of the potential effects may affect individuals on HP diets are blood lipids. Halton and Hu (2004) explained in their work that there is a controversy around this subject, explaining that numerous researches suggesting that short term HP diets are not harmful to blood lipids and future research would be needed.

Regarding cardiovascular disease risk, the Halton and Hu (2004) document pointed that more research is also needed, however, it seems that HP diets are not a risk for cardiovascular condition and maybe even favourable.

Disorders of Bone and Calcium Homeostasis

A study (Delimaris, 2013) reviewed a vast number of researches regarding adverse effects associated with protein intake over the RDA for adults. In a part of this search regarding the effect of HP towards bone disorders and risks of osteoporosis, Delimaris (2013) established that an impropriate balance on the HP diet may produce harmful results on bone, and suggested the relationship between a major vegetable HP intake in favour of an animal HP diet may affect the loss of bone and be exposed to a hip fracture.

Cancer Risk, Liver Function, and Coronary Artery Disease

Furthermore the findings of Delimaris (2013) related to bone disorders, they also review the research of the increase of cancer, disorders of liver function and coronary artery disease due to HP diets, and most of the researchers examined agreed that was due to an HP diet that includes red meat or processed meat. In their conclusion Delimaris (2013) recommend closely guidelines for the HP diet, clinically tested and additional studies for more conclusive evidence.

Conclusion:

After examined several documents regarding HP diet, was not possible to assure that the diet has a great impact while dieting or retaining muscles mass, however, these majority of this studies agreed that in a short-term HP diets shows better results that NP diets and have a major effect in decreasing weight and maintain lean body mass.

All the documents reviewed by this work emphasised the importance of further research information to assert the benefits of this diet and even more, significant risks. Despite a vast of researches investigating the possible causes of health risks related to HP intake, they could not provide much evidence that the HP diet was responsible.

Furthermore, the information exposed that consuming protein over the RDA was not harmful to healthy people, however warm to vulnerable people such individuals with renal disruptions, cardiovascular problem, elderly and diabetes and suggested that HP diets must be clinically tested to reduce any possible hazard.

References:

Astrup, A. (2005) ‘The satiating power of protein—a key to obesity prevention?’, The American Journal of Clinical Nutrition, 82(1), pp. 1–2. doi: 10.1093/ajcn/82.1.1.

Astrup, A. et al. (2008) ‘Protein, weight management, and satiety’, The American Journal of Clinical Nutrition, 87(5), p. 1558S–1561S. doi: 10.1093/ajcn/87.5.1558S.

Campos-Nonato, I., Hernandez, L. and Barquera, S. (2017) ‘Effect of a High-Protein Diet versus Standard-Protein Diet on Weight Loss and Biomarkers of Metabolic Syndrome: A Randomized Clinical Trial’, Obesity Facts, 10(3), pp. 238–251. doi: 10.1159/000471485.

Cuenca-Sánchez, M., Orenes-Piñero, E. and Navas-Carrillo, D. (2015) ‘Controversies Surrounding High-Protein Diet Intake: Satiating Effect and Kidney and Bone Health’, Advances in Nutrition, 6(3), pp. 260–266. doi: 10.3945/an.114.007716.

Delimaris, I. (2013) Adverse Effects Associated with Protein Intake above the Recommended Dietary Allowance for Adults, ISRN Nutrition. doi: 10.5402/2013/126929.

Dror, Y. and Hopp, M. (2014) Hair for brain trade-off, a metabolic bypass for encephalization, SpringerPlus. doi: 10.1186/2193-1801-3-562.

Friedman, A. N. et al. (2012) ‘Comparative Effects of Low-Carbohydrate High-Protein Versus Low-Fat Diets on the Kidney’, Clinical Journal of the American Society of Nephrology. American Society of Nephrology, 7(7), pp. 1103–1111. doi: 10.2215/CJN.11741111.

Halton, T. L. and Hu, F. B. (2004) ‘The Effects of High Protein Diets on Thermogenesis, Satiety and Weight Loss: A Critical Review’, Journal of the American College of Nutrition. Taylor & Francis, 23(5), pp. 373–385. doi: 10.1080/07315724.2004.10719381.

Harvard School of Public Health (2019) The Nutrition Source, hsph.harvard.edu. Available at: https://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/protein/ (Accessed: 6 March 2019).

More references

Layman, D. K. (2004) ‘Protein Quantity and Quality at Levels above the RDA Improves Adult Weight Loss’, Journal of the American College of Nutrition. Taylor & Francis, 23(sup6), p. 631S–636S. doi: 10.1080/07315724.2004.10719435.

Leidy, H. J. et al. (2007) ‘Higher Protein Intake Preserves Lean Mass and Satiety with Weight Loss in Pre-obese and Obese Women’, Obesity. John Wiley & Sons, Ltd, 15(2), pp. 421–429. doi: 10.1038/oby.2007.531.

Loenneke, J. P. et al. (2016) ‘Per meal dose and frequency of protein consumption is associated with lean mass and muscle performance’, Clinical Nutrition, 35(6), pp. 1506–1511. doi: https://doi.org/10.1016/j.clnu.2016.04.002.

Pasiakos, S. M. et al. (2013) ‘Effects of high-protein diets on fat-free mass and muscle protein synthesis following weight loss: a randomized controlled trial’, The FASEB Journal. Federation of American Societies for Experimental Biology, 27(9), pp. 3837–3847. doi: 10.1096/fj.13-230227.

Symons, T. B. et al. (2009) ‘A Moderate Serving of High-Quality Protein Maximally Stimulates Skeletal Muscle Protein Synthesis in Young and Elderly Subjects’, Journal of the American Dietetic Association, 109(9), pp. 1582–1586. doi: https://doi.org/10.1016/j.jada.2009.06.369.

World Health Organisation (2006) Constitution of the World Health Organization – Basic Documents. 45th Suppl. World Health Organization. Available at: https://www.who.int/governance/eb/who_constitution_en.pdf.