Do women really need less protein than men?
The most important determinants of protein needs include:
- Lean mass
- Training/workout regimen
- Body composition goals
- Performance goals
Notice gender isn’t included in that list. Sure, you may need less protein than the 250lb muscle-head bro at the gym who seems to be using the squat rack to improve cell reception while he texts… but that has everything to do with size and training.
When all of these factors are controlled, women functionally have the same daily protein needs as men… typically somewhere in the 1.5-2.0 grams per kilogram of bodyweight range. But, I’m an endurance athlete, that’s way too much! No, it’s not. Research to the rescue.
Let’s take a look at a snapshot of nitrogen balance in endurance-trained women… actually, that’s what the study was called – a snapshot of nitrogen balance in endurance-trained women (Houltham & Rowlands, 2014). For those of you who aren’t sure why I’m talking about nitrogen all of a sudden, just know that nitrogen is used as a marker for protein – it makes up the ‘amino’ part of ‘amino acids’, which are used to build proteins. Normal habitual protein intake in the female athletes averaged 85 grams per day before any dietary interventions (~1.33 grams per kilogram bodyweight). At this level of protein intake, subjects were in negative nitrogen balance – i.e. they were losing more protein than they were consuming – not good for performance, muscle mass maintenance, recovery, etc. They actually had to hit 1.63 grams per kilogram of bodyweight to achieve nitrogen balance – i.e. for protein intake to meet needs. And these needs are no different than those for men.
I’m not saying you have to eat more meat – there are plenty of ways to achieve sufficient protein intake without doing that. But, under-consumption of protein is something I see more frequently in female athletes… and females in general.
Where women do have an advantage…
Now that I’ve convinced you that protein needs are effectively the same between men and women, let’s talk about where they are not. 🙂
During sub-maximal endurance exercise, young women tend to oxidize (burn) less protein than young men (Phillips et al, 1993). That’s it (Markofski & Volpi, 2011). And the difference doesn’t really change practical recommendations all that much. We’re always burning some mixture of carbohydrate, fat, and protein for energy… diet and training strongly impact what that mixture looks like. Women tend to better protect muscle-protein from breakdown during endurance exercise as they rely more heavily on fat stores for energy. Woo hoo!.. if you’re young and doing a lot of endurance exercise, you may need the slightest bit less protein immediately around workouts for optimal recovery and lean mass maintenance or gain.
… otherwise, male and female protein needs are almost exactly the same and depend much more on factors other than gender.
Houltham & Rowlands. A snapshot of nitrogen balance in endurance-trained women. Appl Physiol Nutr Metab. 2014;39(2):219-25.
Phillips, et al. Gender differences in leucine kinetics and nitrogen balance in endurance athletes. J Appl Physiol. 1993;75:2134–2141.
Markofski & Volpi. Protein metabolism in women and men: similarities and disparities. Curr Opin Clin Nutr Metab Care. 2011;14(1):93-7.