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Nutrition Research Review

Research Review: High Protein Intake Impressive Body Comp Results Despite Eating 400 Extra Calories

paleo diet

The effects of a high protein diet on indices of health and body composition a crossover trial in resistance-trained men.

Antonio et al. (2016)

  • The first study to investigate the effect of super high protein on body composition and health in during resistance training.
  • Over 16 weeks, the normal protein group consumed 175 – 200g of protein a day. Whereas, the higher protein group consumed around 230 -250g of protein a day.
  • The high protein group also consumed around 400 more calories a day compared to normal protein group.
  • Despite eating 400 more kcals per day, 75% of the participants showed a slight decrease in fat mass.
  • There were no significant effects on strength or muscular endurance performance between groups.
  • No side effects of a such a high protein intake were noted.
  • Study shows there is no effect of ~175g protein vs ~250g for building muscle. For most people, around 2g protein per kg / bodyweight is sufficient.
  • This study did show a very high protein diet (3g per kg/bw) can help you increase calories without gaining fat – key for bulking, post contest or when “reverse dieting”.


A high protein diet is extremely popular in the fitness industry. This is one of the first studies to examine the correlation between high protein intake and the effect on body composition and other markers of health, whilst coupled with a resistance training program.

A group of resistance-trained males underwent 2 x 8 week trials, whereby they consumed their normal protein intake, followed by a high protein intake ( > 3 g/kg/day; equal to about 200 – 250g of protein a day).

The aim of this study was to assess whether a high protein intake affected health markers, such as liver and kidney function, body composition and performance in resistance trained subjects.


In the normal protein group participants consumed around 2.6 g/kg/day, this equates to approximately 175 – 200g of protein a day; whereas in the higher protein trial participants consumed around 3.3 g/kg/day, equating to about 230 -250g of protein a day.

Over the 16 week trial period, the average protein intake was around 2.9 g/kg/day. Therefore, the average intake over the 16 week period was around 200 – 230g day. Other than the high protein group consuming more calories (approximately 400 more), there were no other differences in carbohydrate or fat intake.

For performance, there was no significant difference between groups when performing a 1-RM bench press strength test or muscular endurance test (RTF at 60 % of the 1-RM bench press).

Although for body composition  the study states there were no significant differences between groups, on an individual level, the graph below shows that despite the high protein group eating around 400 additional calories, 8 of the participants showed a slight decrease in fat mass when consuming higher protein compared to their normal protein diet.


Fat mass

Figure 1: Individual changes in fat mass.

Summary / Key Takeaways:

This is one of the first studies to show that consuming over four times the recommended daily protein intake has no negative effects on health as demonstrated by the participants’ blood results. This supports numerous other studies that show consuming a higher than normal protein intake does not negatively affect kidney, liver or other health markers (in healthy individuals).

This study also highlights that once protein is above 2 g/kg/day, there are minimal differences in muscle gains or performance.

However, the most interesting take-away from this study is that the high protein group ate on average 400 more calories than the normal protein group, yet the majority gained no additional fat. This may make a very high protein diet (> 3 g/kg/day) suitable for higher calorie periods or bulks, when still try to minimize fat gain. It’s also a great tool to use after a contest or long diet when trying to build calories back up whilst minimizing fat gains.

It is important to note that even the normal protein intake levels were significantly higher than an average person’s intake (200g compared to around 50g for a normal individual). This may explain why there were no significant differences in body composition between the two groups.

Past studies investigating the effect of protein intake on body composition have compared a low protein intake of around 0.8 g/kg/day (equal to around 60g of protein per day) and a higher protein group and found a positive effect on body composition. You can read a full research review on high vs low protein intake for fat loss here.

About the author

Rudy Mawer, MSc, CISSN

Rudy has a 1st class BSc in Exercise, Nutrition & Health and a Masters in Exercise & Nutrition Science from the University of Tampa. Rudy currently works as a Human Performance Researcher, Sports Nutritionist and Physique Coach. Over 7 years he has helped over 500 people around the world achieve long last physique transformations.

He now works closely with a variety of professional athletes and teams, including the NBA, USA Athletics, World Triathlon Gold Medalists, Hollywood Celebrities and IFBB Pro Bodybuilders. If you would like to get in contact or work with Rudy please contact him on social media.

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