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I'm currently taking in 100 grams a day of protien via whey powder. I used to take 250 grams when I was training. I've read that you should intake 1 gram per pound of body weight you have when training.

I've also seen numbers such as between 0.8 and 1 gram of protein per kilogram of weight a day (about 7 grams per 20 pounds. So a person who weighs 150 pounds would need around 52 grams a day.)

I'm ~250lbs right now. I was 260 but I'm cutting wieght to 240. I'm not doing any serious training right now.

Edit: To be clear, my question is about how much is too much for the body before seeing side effects such as kidney problems, digestion problems, etc. Not necessarily about wieght loss. At my body weight, how much is too much?

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Mmmm... what is your goal now? Cutting without lose muscle? –  JoaquinG Mar 13 '11 at 13:21
    
pretty much. I do light training to tone. Overall goal is to cut weight and expose my cuts. –  DustinDavis Mar 13 '11 at 16:52
    
If you're going "high" protein, you absolutely NEED to workout some or you will do damage to your kidneys. Exercise stimulates the kidneys (as well as the rest of your internal organs). –  Nathan Wheeler Mar 16 '11 at 17:55
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@Nathan Wheeler: Sources or it isn't true :) No really, people told me that for some time, but consistently failed to produce evidence. If you could provide research, I'd be happy to consider your point. –  LarissaGodzilla Apr 2 at 16:48
    
@LarissaGodzilla - "The average woman should get about 46 grams of protein a day and men should get about 56 grams of protein daily. Active people need more protein than sedentary people, so if you engage in moderate to vigorous exercise on a regular basis, talk to your doctor to see if you should increase your protein intake." - Healthy Eating @ SFGate. –  Nathan Wheeler Apr 28 at 3:49

4 Answers 4

up vote 17 down vote accepted

According to research (Source), the body only needs 0.36g of protein per pound each day for maintenance. In 2009, the American Dietetic Association, Dietitians of Canada, and the American College of Sports Medicine released an abstract supporting 0.5g to 0.8g of protein per pound each day as sufficient (Source).

You can take in a significant amount more than this and be fine, as excess protein is excreted, so long as you get enough fats and/or carbohydrates as well to balance your nutrition needs and solubilize your fat-soluble vitamins that your body requires, as well as calcium to replace that which the protein will leech from your system (Source). You must consume enough water to flush the excess. There's not any point in buying "extra" protein though if you already have plenty in your diet to start with. Those doing body-building will need to be on the high end of this scale.

Based on those research articles, at 250 pounds, the figures are as follows:

  • 0.4g/lb = 100g/day (sedentary)
  • 0.5g/lb = 125g/day
  • 0.6g/lb = 150g/day (active)
  • 0.7g/lb = 175g/day
  • 0.8g/lb = 200g/day (body-building)

Regardless of the amount of calories in your diet, your "necessary" protein will fall into that range of amounts. Anything over that amount will be flushed from the body. If you eat more food, you won't need to also add more protein. The amounts listed above are sufficient. If you eat less food, you won't need to drop protein. Just stay within that range.

If you're cutting pounds, but not doing any serious weight training, you're going to fall somewhere between 0.4g and 0.6g of protein per pound. If you want to take more than that, as long as you're taking in enough fiber, you won't see much in digestive problems, taking in enough calcium will prevent bone density problems, and taking in enough water will prevent kidney problems.

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Why is the excess protein flushed away by the body and not used as an energy source(assuming you didn't eat enough fat/carbs to cover your energy needs)? –  Mr. Roland Dec 11 '12 at 18:02

There is a need to consume more protein during fat loss to spare muscle protein.

This is especially true for Very Low Caloric Diets.

But anything more then 3g per kilogram of body weight seems unnecessary.

2-3g/kg +a couple of sessions of intensive weight training a week could save your muscles while dieting.

I highly recommend books by Lyle McDonald to understand this issue in all the complexity. http://www.bodyrecomposition.com/

Note , that despite being often mentioned, there are zero researches confirming kidney damage by high protein intake for healthy people.

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The information you are asking about is not well known. We know that excess protein can stress the kidneys, but so far there is really no evidence that higher amounts of protein can damage healthy kidneys.

There's a fair amount of evidence that many of us eat too much protein. In addition, countries that eat more animal protein have higher rates of cancer.

My recommendation is to stay closer to the lower end of protein intake and only increase to the point it shows improved performance and no more.

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Can you provide sources for the things you've stated in your second paragraph? –  Nathan Wheeler Mar 16 '11 at 18:07
    
@md5sum: I'm sure you can easily find more information but this is a great start. BTW, the author's credentials are very impressive. –  Jonathan Wood Mar 16 '11 at 18:29
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@Jonathan Wood - I'll just be honest with you... the advertisement for that book looks like a huge amount of hype and tag lines to sell a book. Neither the excerpt nor the main page of the book cite any other comparative research for the statements made. I cannot locate a single official research paper ever published by Dr. T. Colin Campbell. Also, you might want to check this article out as well. –  Nathan Wheeler Mar 16 '11 at 18:49
    
@md5sum: Thanks for the link. I'm on the clock right now and will need to get back to this. I posted the first link I could find and the hype on that page is secondary to the issue. Note that the link doesn't seem to criticize his credentials, which the book goes into great depth about. Clearly, there are elements of optimum protein that are not well understood and controversial. However, this is not the only source that associates particularly red meat with cancer and holds this up as a key reason why Asians seem to suffer less cancer than those in the West. –  Jonathan Wood Mar 16 '11 at 19:49
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It isn't so controversial, as most research has come to the same or close to the same conclusions, as noted by the sources in my answer. Also, "red meat" is not synonymous with "protein". A large portion of the protein in my diet comes from fish, chicken, and eggs. There does seem to be some loose, unproven connection between colon cancer and red meat, but not with protein. –  Nathan Wheeler Mar 16 '11 at 19:53

According M.D. Nick Evans to lose weight need a diet of 50% protein, 40% carbohydrates, 10% fat and a negative caloric balance.

Considering that 1 gr. proteins are 4 kcal then you can calculate how much protein do you need to lose weight without losing muscle mass.

For example: On a diet of 2200 kcal you need to eat 275gr of protein. (2200x0.5) / 4 = 275gr

You just only need to know how many calories you need to eat to be in a negative balance. :-)

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great info. Maybe my question (or comments) are unclear however. Basically, how much can the body handle before you run into side effects (kidneys, digestion, etc)? Not necessarily about weight loss. –  DustinDavis Mar 14 '11 at 4:17
    
It's not clear. For kidneys, it's depends of a lot of things, how much water do you drink, your weight, how much exercise... –  JoaquinG Mar 14 '11 at 8:06
    
@JoaquinG - Can you cite a source for this Nick Evans character and his research? That's a ridiculous amount of protein just for weight loss, and goes far in excess of any research I've ever seen (by about 35%). Also, that's a ridiculously low amount of fat (only 24.5g in a 2200 calorie diet). –  Nathan Wheeler Mar 16 '11 at 18:02
    
I read in this book. [amazon.com/Mens-Body-Sculpting-Nicholas-Evans/dp/0736051414/…. Nick Evans, MD, is an orthopedic surgeon and sports medicine physician in Los Angeles and is a highly regarded authority on strength training, nutrition, and weight-training injuries. He has fostered research in sports injury and performance-enhancing aids and has written for many scientific publications. –  JoaquinG Mar 16 '11 at 18:15
    
@JoaquinG - That book is for bodybuilding. Not for weight loss. And his statement is still contrary to any research ever published on the subject. The point at which you might go onto a diet like that is to drop from 4% body fat to 3% body fat. And still, it's a bit excessive. –  Nathan Wheeler Mar 16 '11 at 18:55

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