How long protein stays in body

Given that muscular development is a function of the dynamic balance between MPS and muscle protein breakdown MPB , both of these variables must be considered in any discussion on dietary protein dosage. Kim et al. Results showed that the higher protein intake promoted a significantly greater whole-body anabolic response, which was primarily attributed to a greater attenuation of protein breakdown. Given that participants ate large, mixed meals as whole foods containing not only protein, but carbohydrates and dietary fats as well, it is logical to speculate that this delayed digestion and absorption of AAs compared to liquid consumption of isolated protein sources.

This, in turn, would have caused a slower release of AA into circulation and hence may have contributed to dose-dependent differences in the anabolic response to protein intake. A notable limitation of the study is that measures of protein balance were taken at the whole-body level and thus not muscle-specific. It therefore can be speculated that some if not much of anti-catabolic benefits associated with higher protein intake was from tissues other than muscle, likely the gut.

Even so, protein turnover in the gut potentially provides an avenue whereby accumulated amino acids can be released into the systemic circulation to be used for MPS, conceivably enhancing anabolic potential [ 25 ]. This hypothesis remains speculative and warrants further investigation.

It would be tempting to attribute these marked reductions in proteolysis to higher insulin responses considering the inclusion of a generous amount of carbohydrate in the meals consumed. Although insulin is often considered an anabolic hormone, its primary role in muscle protein balance is related to anti-catabolic effects [ 26 ]. Given evidence that a 45 g dose of whey protein causes insulin to rise to levels sufficient to maximize net muscle protein balance [ 29 ], it would seem that the additional macronutrients consumed in the study by Kim et al.

Although the previously discussed studies offer insight into how much protein the body can utilize in a given feeding, acute anabolic responses are not necessarily associated with long-term muscular gains [ 30 ].

Wilborn et al. Similarly, a lack of between-group differences in lean mass gain was found by Fabre et al. In a day study of elderly women, Arnal et al. A follow-up study by the same lab in young women reported similar effects of pulse versus spread patterns of protein intake [ 34 ]. The combined findings of these studies indicate that muscle mass is not negatively affected by consuming the majority of daily protein as a large bolus.

However, neither study employed regimented resistance training thereby limiting generalizability to individuals involved in intense exercise programs. Insights into the effects of protein dosage can also be gleaned from studies on intermittent fasting IF.

Typical IF protocols require intake of daily nutrients, including protein, in a narrow time-frame — usually less than 8 h — followed by a prolonged fast. A recent systematic review concluded that IF has similar effects on fat-free mass compared with continuous eating protocols [ 35 ]. However, the studies reviewed in the analysis generally involved suboptimal protein intakes consumed as part of a low-energy diet without a resistance training component, again limiting the ability to extrapolate findings to resistance-trained individuals.

Helping to fill this literature gap is an 8-week trial by Tinsley et al. The TRF group lost body weight via lower energy intake kcal less on fasting vs. Perhaps most interestingly, biceps brachii and rectus femoris cross sectional area showed similar increases in both groups despite the h fasting cycles and concentrated feeding cycles in TRF, suggesting that the utilization of protein intake in the ad libitum 4-h feeding cycles was not hampered by an acute ceiling of anabolism.

Unfortunately, protein and enrgy were not equated in this study. Subsequently, an 8-week trial by Moro et al. These findings further call into question the concern for breaching a certain threshold of protein intake per meal for the goal of muscle retention.

In contrast to the above findings showing neutral-to-positive effects of a temporally concentrated meal intake, Arciero et al. During the initial day eucaloric phase, HP3 and HP6 consumed protein at 2. HP6 was the only goup that significantly gained lean mass. During the subsequent day eucaloric phase, HP3 and HP6 consumed protein at 1. HP6 maintained its lean mass gain, outperforming the other 2 treatments in this respect HP actually showed a significant loss of lean mass compared to the control.

In any case, it is notable that comparisons in this vein specifically geared toward the goal of muscle gain, hypercaloric comparisons in particular, are lacking. An important distinction needs to be made between acute meal challenges comparing different protein amounts including serial feedings in the acute phase following resistance training and chronic meal feedings comparing different protein distributions through the day, over the course of several weeks or months.

Longitudinal studies examining body composition have not consistently corroborated the results of acute studies examining muscle protein flux. Quantifying a maximum amount of protein per meal that can be utilized for muscle anabolism has been a challenging pursuit due to the multitude of variables open for investigation. Perhaps the most comprehensive synthesis of findings in this area has been done by Morton et al.

This was based on the addition of two standard deviations to their finding that 0. In line with this hypothesis, Moore et al. Importantly, these estimates are based on the sole provision of a rapidly digesting protein source that would conceivably increase potential for oxidation of AA when consumed in larger boluses. It seems logical that a slower-acting protein source, particularly when consumed in combination with other macronutrients, would delay absorption and thus enhance the utilization of the constituent AA.

However, the practical implications of this phenomenon remain speculative and questionable [ 21 ]. The collective body of evidence indicates that total daily protein intake for the goal of maximizing resistance training-induced gains in muscle mass and strength is approximately 1. However, 1. Bandegan et al.

This reinforces the practical need to individualize dietary programming, and remain open to exceeding estimated averages. It is therefore a relatively simple and elegant solution to consume protein at a target intake of 0.

Using the upper CI daily intake of 2. This tactic would apply what is currently known to maximize acute anabolic responses as well as chronic anabolic adaptations. Further research is nevertheless needed to quantify a specific upper threshold for per-meal protein intake.

Brad Schoenfeld conceived of the article. Both authors equally contributed to the writing of the manuscript. Both authors read and approved the final manuscript. Brad Schoenfeld serves on the scientific advisory board for Dymatize Nutrition. The authors declare no other conflicts of interest. Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. Brad Jon Schoenfeld, Email: moc. Today's Top Stories. How to Eat Like Chris Hemsworth.

Men's Health. You may be able to find the same content in another format, or you may be able to find more information, at their web site. Chris Mohr, Ph. This content is created and maintained by a third party, and imported onto this page to help users provide their email addresses. You may be able to find more information about this and similar content at piano. Advertisement - Continue Reading Below. The stuff is an integral component of every cell in your body, including, yes, your muscles.

That process of damage and repair is what maintains and grows your muscle mass. But protein is not just important for people who work out: In addition to muscle growth and repair, protein is essential to the growth and repair of virtually all cells and body tissues—from your skin, hair, and nails to your bones, organs, and bodily fluids, according to the FDA. Protein also plays a role in crucial bodily functions like blood clotting, immune system response, vision, fluid balance, and the production of various enzymes and hormones, per the FDA.

And because it contains calories, it can provide the body energy for storage or use. Dietary protein gets broken down and reassembled into the various kinds of proteins that exist in the body. Tewksbury explains, through the digestive process. Then those little singular amino acids get reconfigured by the liver into whatever kind of protein your body needs. For instance, some proteins in the body make up antibodies that help the immune system fight bacteria and viruses. Rarely, if your body is in a fasting state or not getting enough calories coming in from other macronutrients, broken-down protein can be converted into glucose and used for emergency fuel, Whitney Linsenmeyer , Ph.

But this is not typical, because the body prefers carbs as its primary source of energy followed by dietary fat, if the body is not getting enough carbs. Linsenmeyer says. Okay, so how much protein are we talking about here? The amount of protein your body actually requires for the purpose of tissue growth and repair is determined by factors like sex, age, height, weight, health, activity level, and overall calorie need, according to the U. The RDA for protein is 0. So you would multiply your weight in pounds by 0.

For instance, the average pound person needs at least 72 grams of protein per day to meet the RDA. People with a higher activity level will likely need more. Gonzalez , Ph. How much more, exactly, depends on factors like how much you exercise and your body composition goals, as SELF has reported —as well as who you ask. Based on those recommendations, for instance, a pound person would want to get between and grams of protein a day. Gonzalez says. When you eat your protein is just as important as how much you eat.