Rethinking Protein: Why the RDA May Not Be Enough for Optimal Health

Earlier in the year, we discussed the medical power of muscle mass and its importance on longevity and health. Today, we’re discussing the importance of dietary protein to support muscle mass and strength improvements. If wanting to lose weight, dietary protein is definitely something to ensure you’re getting enough. So, what does the research say is enough?

The recommended dietary allowance for protein is set at 0.8g per kilogram (kg) of body weight, or, because 2.2 pounds is equivalent to 1 kilogram, about 0.4g (0.36g) per pound of body weight. Science uses the metric system and macronutrients have always been in grams. We understand this. But knowing your weight in kilograms is not the norm unless you work with the metric system as part of your job or schooling. Divide your body weight by 2.2 to get weight in kilograms.

The 0.8g per kg of body weight was established as a minimum amount of protein to preserve nitrogen balance. Nitrogen is a fundamental part of all amino acids, the building blocks of proteins. Your body uses nitrogen primarily as a key component of amino acids and nucleic acids, which are essential for building and repairing tissue, creating enzymes, and carrying genetic information. Nitrogen is also found in other vital biomolecules like neurotransmitters, hormones, and vitamins. Your body needs to maintain a balance between the nitrogen you consume and the nitrogen you excrete, a measurement used to assess protein status.

Why am I taking the time to explain nitrogen in food? Understanding the why behind something strengthens our commitment to it—making us more willing to support, embrace, and put it into action. It’s why I’m always digging, hunting.

In a weight loss study¹ involving young males, participants engaged in full-body strength training workouts two times per week for 4 weeks and were divided into protein groups at 1.2g per kg of bodyweight and 2.4g per kg of bodyweight.

Despite consuming about 180 more calories per day, the 2.4 group lost more fat, than the 1.2 group (10.6 lb vs 7.7 lb respectively). One contributing factor could be that the body burns more calories to metabolize protein compared to carbohydrates and fats. In other words, your body works a little harder to process protein.

The 2.4 group also gained much more lean mass than the 1.2 group (2.6 lb vs 0.2 lb). As a reminder, lean body mass is muscle mass.

Another study² without weight loss focus was performed in older adults and included twice-a-week strength training with two groups for protein intake at 1.0g per kg of bodyweight and 1.3g per kg of bodyweight. Both groups had increases in strength and physical performance. However, the 1.0 group lost 0.6 lb of lean body mass at 24 weeks whereas the 1.3 group gained 2.8 lb of lean mass.

After age 60, we lose up to 3% per year of lean mass. The only way to combat this is good nutrition and regular exercise (as mentioned two weeks ago).

Evidence from a meta-analysis³ assessed data from numerous individual studies determined 1.6g per kg of bodyweight (or 0.7g per pound) to be the optimal amount of protein per day for improving muscle mass.

The takeaway is that, while strength training is the most important, protein consumption still has a significant effect on lean body mass changes that will occur in association with strength training. If you don’t lift, it won’t grow. While it takes extra work, protein can be just as easily converted to fat if it’s not supporting muscle mass because of the demands of strength training.

For comparison, when I was competing, I consumed about 200g of protein per day. In fact, by noon, I’d consumed nearly half the amount of my daily protein goal. My off-season bodyweight was 148-150 lb and my competition weight was 139 to 141 lb. That’s nearly 1.4g per lb of body weight (or 3g per kg). That’s a lot of protein. My purpose was all about good weight gain (lean mass) and my lifting intensity matched my protein intake.

Clearly this was for a particular purpose as a highly competitive athlete on a national and international stage.

At the end of the day, during weight loss 1.2g of protein per kg of bodyweight per day (0.5g per lb) may be enough to prevent loss of lean mass, but 1.6g per kg  (0.7g per lb) or more may provide additional benefit, particularly for highly active individuals.

Be sure your water intake is above norms as your body uses more water for protein synthesis. If you’re eating a higher protein diet you need to drink more water.

If you have questions about this article, email me.

References

1. The American Journal of Clinical Nutrition. 2016. Vol 103, Issue 3, pgs 738-746. T. Longland, et al. Higher compared with lower dietary protein during an energy deficit combined with intense exercise promotes greater lean mass gain and fat mass loss: a randomized trial.
2. Journal of the American Medical Directors Association. 2012. Vol 13, Issue 8, p713-719. M. Tieland, et al. Protein Supplementation Increases Muscle Mass Gain During Prolonged Resistance-Type Exercise Training in Frail Elderly People: A Randomized, Double-Blind, Placebo-Controlled Trial.
3. Journal of Cachexia, Sarcopenia and Muscle. 2022. N. Everson, et al. Systematic review and meta-analysis of protein intake to support muscle mass and function in healthy adults.