When venturing on a quest to either lose weight, gain weight (in the form of muscle mass), and/or maintain weight, monitoring your protein intake is a dietary habit that will help you achieve any one of these goals successfully. Protein is an awfully overlooked yet powerful tool in influencing energy balance and ultimately influencing body weight. Increasing your protein intake will help you build and maintain muscle mass, feel more satiated, and acutely increase your metabolism due to its thermic effect. This article will help you understand why having a relatively high protein intake is favorable to achieve these outcomes and will give you science-based estimations for the daily amount of protein to consume.
#1) Retain/Build Muscle Mass
Increasing your protein intake while also engaging in a regular resistance training program has been shown to increase muscle mass and strength. Increasing your muscle mass is critical to optimal daily function and metabolic health. Muscle mass is the main contributing factor to your resting metabolic rate which determines how many calories you expend at rest. This number makes up approximately 60% of your total daily energy expenditure making it a value that is crucial in determining energy balance and weight regulation.
Increasing your protein intake coupled with resistance training will also help you maintain muscle while being in a negative energy balance. Being in a negative energy balance, or energy deficit, leads to weight loss which can be derived from fat tissue, muscle tissue, water, and other sources within the body. Approximately 25% of weight lost while in an energy deficit is lean body mass with a significant amount of that lean body mass coming from muscle tissue. As mentioned previously, muscle mass is a critical factor in determining your resting metabolic rate making it a body tissue that is not ideal to lose during weight loss. Increasing your protein intake can help mitigate the risk of losing muscle mass during an energy deficit.
A study by Areta et. al. showed that engaging in resistance training and consuming a relatively-high protein intake helped preserve lean body mass while losing body weight. In this study, participants who consumed 1.2 g/kg of protein per day (0.55g/lb/day) in conjunction with strength training 6 times per week retained their lean body mass over a 4 week period. Even more interesting, however, is another group who consumed 2.4 g/kg (1.09g/lb) of protein per day (3x the recommended daily allowance) in conjunction with strength training 6 times per week increased their lean body mass over the 4 week period. This study shows that increasing your protein intake well above the daily recommended amount may be beneficial to retaining muscle mass and preserving metabolic rate and health.
#2) Feel Satiated
One of the main downsides of being in an energy deficit is the lack of feeling satiated post-feeding. This sensation is often due to the fact that your body’s energetic demands are not being met under these restrictive conditions. One of many options to combat this feeling is eating a diet higher in protein.
Satiety is regulated by a multitude of systems within the body including the endocrine system, the cognitive and neural system, and the gastrointestinal system. According to a National Center for Biotechnology Information article titled, “A high-protein diet for reducing body fat: mechanisms and possible caveats” a high protein diet can affect these systems that regulate our appetite. This article listed a study that used a standard tool to assess subjective appetite and satiety called a visual analogue scale. This scale showed that satiety was greatly increased after a meal containing 60% calories from protein as opposed to a meal only containing 19% calories from protein. Another study by Crovetti et al. confirmed these findings by showing that a meal containing 68% calories from protein was far more satiating than a meal containing only 10% calories from protein. These studies show that increasing protein intake per meal can lead to increased feelings of satiety and help maintain a reduced caloric intake overtime.
#3) Increase Your Metabolism (Acutely)
Metabolism is a multi-faceted mechanism that ultimately determines your body weight. There are four main parts of metabolism that affect the amount of calories you expend daily. These parts include: resting energy expenditure (~60%), non-exercise activity thermogenesis (~20%), exercise activity thermogenesis (~10%), and the thermic effect of food (~10). These factors combine to determine how many calories you expend daily and influence your body weight.
Consuming a high protein diet can positively affect the last and seemingly least important part of the equation – the thermic effect of food. The thermic effect of food is the increased metabolic demand post food ingestion. An NCBI article titled “Diet induced thermogenesis” states that “although DIT [thermic effect of food] is the smallest component, it could play a role in the development and/or maintenance of obesity.” This means that the thermic effect of food, although not incredibly significant, still plays an important role in managing body weight.
The thermic effect of food differs between different macronutrients. According to the NCBI DIT article mentioned above, TEF values for protein are 20-30% meaning 20-30% of protein calories are used during metabolism for nutrient breakdown. Compared to other macronutrients such as fat (0-3%), carbohydrates (5-10%), and even alcohol (10-30%), protein has the highest TEF value inducing the greatest metabolic rate increase. This higher thermic effect of food has implications for the effect of nutrients on weight regulation. Although this point is not incredibly significant, it is still worth considering when trying to lose and/or maintain body weight.
There are many reasons to increase protein intake, especially under conditions of energy restriction, maintenance, and even energy surplus. Consuming a diet higher in protein can help you build/maintain muscle mass, feel more satiated, and even acutely increase your metabolism, all of which help in the regulation of body weight. For more information on the sources cited in this article, visit these links listed below:
- Dietary Protein & Muscle Mass: Translating Science to Application & Health Benefit
- Dietary Protein, Weight Loss, & Weight Maintenance
- Recent Perspectives Regarding the Role of Dietary Protein for the Promotion of Muscle Hypertrophy w/ Resistance Exercise Training
- A High-Protein Diet for Reducing Body Fat: Mechanisms & Possible Caveats
- Diet-Induced Thermogenesis
- Revised Reference Values for the Intake of Protein
- Dietary Protein for Athletes: From Requirements to Optimum Adaptation