Question about too much protein.

Since you are only taking in a large amount of protein in a short period of time (during the 90 days of P90X), you will be fine. Its when you take large amounts of protein over a long period of time that can do damage to your kidneys. I recommend following the P90X guidelines while you are doing the program. But thats only my opinion. Hope that helps!

This may sound like I am directing it at you personally, but I am not. I am posing a rhetorical question to the general population on this blog.

You have two sources of information here:

One is a major university nutritional studies department, which is presenting the information in great detail.

The other is an informercial.

Why would there be any question in your mind as to which is the most accurate source of information?

I agree with what other posters said. And when people ask me what I recommend, I usually tell people that if they do moderate to high level exercising at least 4 times a week, 20 to 30% of their calories should come from protein. I usually see very few reasons to go above this, I don't have a serious issue with 35% but that's about the tops for me. 40% is too much IMHO, and yeah, I've looked at the P90X program and just can't figure out why they go that high, it doesn't do anything for you to eat that much protein, not muscle wise at least.

As for the website, it looks relatively accurate to me, I can't see any serious flaws in most of their logic. Some of the numbers are slightly debatable, but not off by a large margin IMHO.

Personally, I prefer (and usually recommend to others) a 50/28/22 carbs/protein/fat ratio, or for someone just doing mainly cardio with little resistance it can be more of a 50/25/25 ratio. But anything from 55/23/22 to 45/30/25 is ok in my book. Lower than 20% in protein is ok I guess (down to about 16%) but I see no reason for it unless you are trying to lose muscle mass (which is something few want to do on this site).

It seems to me you should start off with your total calorie needs, your total protein needs, based on body weight, and work from there. To me that makes a lot more sense than starting off with an arbitrary %.

The consensus of the literature that I have read (excluding the extreme muscleheads) is that 1.5 g per kg of body weight is the upper limit of what is effective (and that's primarily for beginners--the longer you lift the less protein you need, and probably most people do not need the 1.5). I have also seen at least one or two references that have shown additional weight loss benefits in females who consumed at least 100g of protein--I think that was regardless of body weight.

My example: 90 kg x 1.5 is 135 g of protein per day. That's 540 calories a day on days when I am working out. At a maintenance diet of 2200 Cal/day + the 800 or so I burn on a typical exercise day, that's 18%. To me that is an "upper limit" scenario. I personally do just fine on 1g/kg per day or less of protein. Actually, if I go too high on protein I start to "bonk" during my workouts.

A lower-weight, highly active endurance athlete can easily consume the recommended 1.6 g/kg of protein on as little as 12%-15% of total calories. I would think that a smaller non-athletic female trying to loose weight on a 1200 Kcal/day diet might be better served by the 30%+ ratio. Again, I don't think the diet should originate from the ratio--it should be just the opposite.

The need for protein is pretty straightforward: conserve lean body mass, esp during calorie restriction; provide a sufficient pool of amino acids for assimilation and repair, help provide a feeling a satiety and control hunger impulses, and MAYBE provide an extra thermogenic effect from digestion. And the benefits are not dose-related once minimum needs are met.

IMO, there are very few people--on this website or in the general population--that are doing enough volume of intense exercise that they even need to spend 5 min thinking about their protein intake. But there are $$$ tens of millions to be made, so the subject is constantly being pounded into people's brains. If many people put 1/2 the effort into their workout routines that they put into planning their protein intake, they would see much better results.

I think that many of the "ratios" that are thrown about are determined as much, if not more, by ideology than by science. They are used as badges of identification for different political (philosophical, not Dem/Repub) groups.

Great Post! Does anyone know what does MFP set the carb/protein/fat percentages to? (the default)

I found it. The MFP defaults for carb, protein, and fat are: 55/15/30

I'm currently doing Insanity and eating 40-40-20, and then I'll be doing P90X. Now that you guys have posted this material though, I don't plan on eating like this for the long run. Thanks for posting this all!!