High protein intake: friend or foe? Evidences

juzaam · June 2013

Daily protein intake is a "hot topic". Some say you should have a high protein intake (30%) to boost your weight loss, others say that's completely unnecessary, others say it's dangerous for your kidneys.

I am a physician, a MyFP passionate and avid researcher, so in this brief post I will try to cover the main aspects of the real world in a Q&A format, I hope it helps you for your diet.

1) How much protein do I need to survive?: FDA reccomends 0.8 g protein / kilo / daily. That would be around 50 g for a 60 kg woman and 64 g for a 80kg man.

2) Who says to increase the protein intake and why ? We have two scenarios here: A and B.

A) The avid bodybuilder who hopes to gain more muscle if he increases protein intake. This is FALSE. (http://www.ncbi.nlm.nih.gov/pubmed/22718030) Eating MORE proteins will not boost your muscle growth. A small caloric surplus and progressive overload in weight training will do that for you, at a very slow pace. A good caloric surplus would be 250 calories over your manteinance level, in a combined protein / carbs form.
If you take care of this and follow a variated and complete diet (which of course comprises protein-rich food), since you're on a 2500-3000 cals your recommended protein intake for muscle growth will be already met.
Without anabolic hormons, there is very little that you can do to alter your normal muscle growth rate.

The regular guy / girl who is following a strict diet and reads about increasing protein to 1-1.2 g /kg/ day to help results. This is TRUE FOR FAT LOSS, not for WEIGHT LOSS in general.
If you are on a caloric deficit, chances are that you are eating very low quantity of proteins. But if you want to burn only FAT and limit Muscle reduction, you MUST tell this to your body somehow. Workout and increased protein intake is your way to tell your body " I am transforming my diet. This adjustements I have made must reflect the way YOU change. We only want muscles here, get rid of the fat" .
This is more important for the males rather than females. An "ideal" female body doesn't usually have lots of muscle in comparison. Additionally, in a female, muscles would not grow over a certain limit because of lack of testosterone. Hence, for a female, weight loss usually reflects more appropriately fat loss, because there is not that much muscle to get rid of.
If you are a girl, high protein intake will help you less than if you are a guy.

3) What happens if I eat only proteins and get rid of carbs and fat? This is a stupid idea, don't do that. If any diet you are following (Dukan or anything else) brings you to this, quit it. Eating only proteins without sufficient carbs/fats increases ketogenesis. Sure, you will see some results shortly, but you'll put your body in a fasting state, in which he will be forced to derive everything he needs from proteins, altering blood PH and putting you at risk for disease. Additionally, you will gain most of the weight again when you return to a traditional diet, because you have not learned a new eating habit and because your metabolism went simply nuts.

4) Will my kidneys be threatened on 1.2g / kg / daily of proteins and a complete diet ? NO. In fact, it has been proven that up to an amazing 2.8g /kg/ daily there is no change at all in a healthy kidney's functions . (http://www.ncbi.nlm.nih.gov/pubmed/10722779)

5) Is there any other reason why I should increase protein in my diet? Protein scientifically satiates you more, takes more to digest and wastes more calories in digestion also. However, do not expect that this will make it up for a bad diet or binging habits.
It's just a small bonus that comes as a prize for dieting well and it has to fight with the psychological drive for food (i.e. binging habits) that are the main reason why you are here. We tend to overeat out of boredom, depression or junk food addictive properties.

CONCLUSION : Caloric deficit is the MOST if not the SOLE actor of your weight and fat loss. If you are a young man who wants to minimize muscle loss during the diet for esthetic / athletic reasons, then you can safely consider an increase of protein intake up to 1-1.5 g kg / daily, provided that you do not overeat calories in the process. Additionally, if you tried high proteins food and felt that they help you respecting your caloric limits, then this is another case in which you can give it a try.
If you have no interest in this, you have no obligation to do so. Your caloric deficit will however bring you to your goals, sooner or later.
But remember: at least 0.8 grams /kg /daily in any diet.

No health issues for a healthy person. Consult your physician in any other case !

Francl27 · June 2013

Good to know, I'm still sticking to higher proteins because it keeps me fuller, lol.

d9123 · June 2013

i eat moderate, about 120 - 150g. I weigh 178lbs. Am i doin it right?

aelunyu · June 2013

Interesting! I am interested, always especially when physicians are involved.

But I must play devil's advocate. You say avid bodybuilders look to increase protein intake as a correlate of increased muscle size/density. True, though you reference a study where the subjects are nowhere near producing the work load and volumes of an avid bodybuilder. Twice a week which I am assuming can only be full body workouts with a frequency of 2 per 7 days is hardly considered avid bodybuilding.

I concede to the point that most bodybuilders are probably eating more protein than they need, though the sensible ones are not doing so as a marker of what they believe to be a required amount of protein, but instead as a result of a specific macronutrient ratios that they believe to produce optimal performance and recovery...combine this with a minimal maintenance level of total calories, and by default the protein numbers tend to be in the higher range.

If a bodybuilder who trains 5 times a week is given an 3000 calorie diet, and assuming he is intaking the upper range of carbohydrate (500g/day), and a moderate range of fat (80g), the left over protein allowment is still going to be higher than the RDA. Much higher. If he were to injest more carb, he would not see increased glycogen synthesis. If he were to ingest more fat, he would not reap the benefits of better endocrine function or enhanced insulin sensitivity. What he gains from over-ingesting protein is the promise of a positive nitrogen balance for most of his 24 hour day. Therefore, assured protein synthesis, most likely (though you are correct that there is a genetic limit to how much synthesis is actually achieved per individual)

There is no fault in assuming a 250 surplus will lead to increased lean body mass. There is folly in the assumption that a 250 surplus is optimal. If the goal is to amass lean tissue in a short time, the logic extends that we'd eat much more than a 250 calorie surplus. Assuming our genetic ability to partition nutrients between fat, glycogen, and muscle cannot be changed in any way (a point you reference to yourself), ingestion of something like 700 over maintenance, coupled with intense training will see you gain weight theoretically at 1lb a week (3500 calories) in the ratio of muscle-fat that your body genetically already preordains.

Very concise post. For the most part I like it.

juzaam · June 2013

Thanks for your interesting considerations!

I see no disagreement here, only different calculations.
You correctly talk about 700 caloric surplus over manteinance. My 250 caloric surplus is intended over the calories you burn during training. A strong bodybuilder with intention to put mass may easily waste 450 during training, so I think we reach more or less your cited 700. I should have specified that though, it may be misunderstood.

However, I would not eat 700 surplus on the day I don't train. And I would not go for a five-days routine , but I am no bodybuilder also

pestopoli · June 2013

i eat moderate, about 120 - 150g. I weigh 178lbs. Am i doin it right?

To judge by your profile pic, I'd say you're doing it right

juzaam · June 2013

i eat moderate, about 120 - 150g. I weigh 178lbs. Am i doin it right?

It's a safe and efficient target in my opinion. I am doing the same and I am the same weight as you.
As long as u keep the caloric target, of course

aelunyu · June 2013

Yep, actually you pose some very valid points. The stigma of high protein being bad for kidneys for example, is so unfounded in healthy individuals. Great post, for sure!

Casstevens133 · June 2013

I'm interested in this topic too. I generally go over on protein and under on carbs. I've lost 29lb since January so have no reason to change but opinions would be appreciated. My diary is open so feel free to have a look and let me know what you think. Must admit
I'm pretty happy with what I'm doing as this is a lifestyle for me not just a diet !! Thank you for your input

PS I work in an office and my exercise tends to be dog walking, archery and gardening

juzaam · June 2013

Hey Carol,
I took a look and sounds good to me! You are doing fine!

Carbs are vital to your brain. He can burn only glucose or ketones and he needs 500cals/day, no matter your activities, study, workout , nothing whatsoever .
The rest of your body will be happy with fat, protein and occasional carbs. Your heart, for instance, is a far burning machine. In fact, around 70% of its energy comes from fat.

So my reccomendation would be to not stay below 500 cals/day from carbs for a long time ok? Some times because your body can store them, but do not starve him of carbs.

Additionally , always consider a multivitamin supplement when on a diet.

I'm interested in this topic too. I generally go over on protein and under on carbs. I've lost 29lb since January so have no reason to change but opinions would be appreciated. My diary is open so feel free to have a look and let me know what you think. Must admit
I'm pretty happy with what I'm doing as this is a lifestyle for me not just a diet !! Thank you for your input

PS I work in an office and my exercise tends to be dog walking, archery and gardening

BarackMeLikeAHurricane · June 2013

Hey Carol,
I took a look and sounds good to me! You are doing fine!

Carbs are vital to your brain. He can burn only glucose or ketones and he needs 500cals/day, no matter your activities, study, workout , nothing whatsoever .
The rest of your body will be happy with fat, protein and occasional carbs. Your heart, for instance, is a far burning machine. In fact, around 70% of its energy comes from fat.

So my reccomendation would be to not stay below 500 cals/day from carbs for a long time ok? Some times because your body can store them, but do not starve him of carbs.

Additionally , always consider a multivitamin supplement when on a diet.

I'm interested in this topic too. I generally go over on protein and under on carbs. I've lost 29lb since January so have no reason to change but opinions would be appreciated. My diary is open so feel free to have a look and let me know what you think. Must admit
I'm pretty happy with what I'm doing as this is a lifestyle for me not just a diet !! Thank you for your input

PS I work in an office and my exercise tends to be dog walking, archery and gardening

First issue-You even mentioned that your brain can function on ketones instead of glucose so I don't understand why you're claiming carbs are essential. Ketones are a result of breaking down fats and protein. Second issue-You don't need to eat carbs to provide your body with glucose. Your body is capable of converting protein into glucose via de novo gluconeogenesis.

juzaam · June 2013

Hello, thanks for your conyribution

You are right in both issues. The problem lies in the fact that ketones are not as good fuel as carbs are. Produce too much of them and you may risk Ketosis, which Wikipedia can explain surely better than me. http://en.m.wikipedia.org/wiki/Ketosis
That's why my safety advice is to stick with carbs. I mean, do not avoid them completely. I am against the ketogenic diet approach. Gluconeogenesis comes at a price. Of course you will find different opinions at regard.

First issue-You even mentioned that your brain can function on ketones instead of glucose so I don't understand why you're claiming carbs are essential. Ketones are a result of breaking down fats and protein. Second issue-You don't need to eat carbs to provide your body with glucose. Your body is capable of converting protein into glucose via de novo gluconeogenesis.

mrmagee3 · June 2013

Hello, thanks for your conyribution
You are right in both issues. The problem lies in the fact that ketones are not as good fuel as carbs are. Produce too much of them and you may risk Ketosis, which Wikipedia can explain surely better than me. http://en.m.wikipedia.org/wiki/Ketosis
That's why my safety advice is to stick with carbs. I mean, do not avoid them completely. I am against the ketogenic diet approach. Gluconeogenesis comes at a price. Of course you will find different opinions at regard.

Can you please explain more as to why you are against the ketogenic diet approach, and why ketosis is a "risk" for those who don't already present with underlying complications (such as pancreatic exhaustion/T1 diabetes)? Also, what role, if any, do you feel that hormones play in fat accumulation/oxidation?

Casstevens133 · June 2013

Thank you for your feedback - I feel 100% better for cutting out all the pastry, cheese etc. no more indigestion, spots (yes at the age of 56!!) and I've even cut way back on my asthma inhalers which is a huge bonus. Joints are much better too - low grade arthritis was starting to kick in. Don't currently take multi vitamins but will give it serious consideration. Thank you again

JillSalus · June 2013

Bump for later, interesting topic.

ETA: I can't spell

Matt_Wild · June 2013

Let’s talk about what we know, it is clear that the optimal protein intake is higher than some recommendations; in one study it was shown that a protein intake of 2.1g/kg provided superior muscle mass gains to a protein intake of 1.2g/kg in weightlifters (Tipton et al, 2004).

It is also known that even in a very slight caloric deficit (~100kcals) while performing high levels of activity, the upper levels of the recommended protein intake for athletes (2.0g/kg) are not always sufficient to maintain nitrogen balance (Manninen 2004).

So we know that eating slightly more than the upper level of the generally recommended protein intakes for athletes is better than the low end of the current recommendations. We also know that the current upper level recommendations are precarious with regards to muscle maintenance while on a diet, even if the caloric deficit is very mild.

Lastly, it has been shown that intakes as high as 3.0g/kg (or 40% of calories) have no significant health risks (Tipton et al, 2004). So, not only are the current recommendations suboptimal for weight lifters, and not enough to maintain muscle mass while doing high levels of activity on a diet, but higher intakes seem to have no risks.

Another important point made in some more recent studies, is that Muscle Protein Synthesis (MPS) is increased in a dose-dependent fashion in response to protein. Therefore, it may be more useful to suggest a per meal protein intake in addition to a daily total. Since maximal muscle growth occurs due to an increase in MPS, it may be optimal to focus not only on total protein intake, but also frequency and amount of protein at each meal. In fact, in the most recent research it has been shown that MPS is maximally stimulated by 3-4g of the branch chain amino acid Leucine (or .05g/kg of Leucine), and that it can only be maximally stimulated every four to six hours..

This research is the first of its kind in that it examines not only nitrogen balance, but the MPS gene-signaling effects of amino acids. Depending on protein source, it typically takes anywhere from 30-50g of protein to meet the 3-4g Leucine requirement. Based on the frequency MPS can be stimulated, this suggests an optimal protein intake for muscle growth close to 2.5-3.0g/kg (Norton et al, 2009). So, It would appear that higher than normally recommended protein intakes might be prudent for athletes looking to gain muscle mass or maintain it while dieting. For those that are metric-system challenged, 2.5-3.0g/kg would be right around 1.1-1.4g/lb, so a 200lb male bodybuilder would benefit from eating 220-280g of protein daily, evenly divided into meals every 4-6 hours, more if dieting, less if eating at maintenance or in a gaining phase.

So if protein is safe at higher levels, and most athletes need to eat more, why am I not simply telling you “the more the better”? Wouldn't that just fit nicely with the “go hard or go home”, “train insane or remain the same”, “bigger is better” attitude of the bodybuilding community?

Well, I'm here to tell you that while bodybuilders might have it right in-that more protein is needed than was previously thought, the attitude of “more is better” is what leads most of my bodybuilding brethren astray; the classic quote “more is not better, better is better” comes to mind.

Tipton, K. D., & Wolfe, R. R. (2004). Protein and amino acids for athletes. Journal of Sports Sciences, 22(1), 65-79.

Norton, L., E., & Wilson, G. J. (2009). Optimal protein intake to maximize muscle protein synthesis: Examinations of optimal meal protein intake and frequency for athletes. Agro Food Industry High-Tech, 20(2): 54-57.

Manninen, M. H. (2004). High -Protein Weight Loss Diets and Purported Adverse Effects: Where is the Evidence? Journal of the International Society of Sports Nutrition, 1(1): 45-51.

Blueyedtine · June 2013

Bump! This is getting good...

juzaam · June 2013

Can you please explain more as to why you are against the ketogenic diet approach, and why ketosis is a "risk" for those who don't already present with underlying complications (such as pancreatic exhaustion/T1 diabetes)? Also, what role, if any, do you feel that hormones play in fat accumulation/oxidation?

Thanks for your interesting contribution in the matter.
Ketogenic diet has been proposed for a long time. It works in terms of weight loss, but it comes at a price. High price in my opinion:

1) You are more likely to lose weight than fat on a ketogenic diet, compared to a complete diet.
2) You are more likely to regain your weight when you start again introducing carbs in your diet (this has to do with insuline and cortisol, explained later)
3) You are weaker on a ketogenic diet when doing cardiovascular or endurance. For non-athletes, however, it may be difficult to notice the difference.
4) Ketogenic diet causes low insulin, which some say is of help to prevent insulin resistance. They forget to specify that a healthy normocaloric diet does not expose you to the amount of glucose from refined carbs that is the true responsible of pandemy of insuline resistance in our planet. So you prevent something that you should avoid in the first place.
5) At the same time, instead, ketogenic diet causes an increase of cortisol. This triggers the same side effects as a prolonged steroid therapy, which you have already heard of: fat accumulation, immunity depression, loss of memory, skin weakness, early aging.
6) Cholesterol levels may increase by around 30% and with it the risk of high cholesterolemy.
7 ) Acidosis increases bone demineralisation.
8) Excess calcium in the urine (hypercalciuria) occurs due to increased bone demineralisation with acidosis. The pH of the urine changes from neutral to slightly acidic, which can put stress on the kidneys and potentially raise the risk of developing kidney stones.
9) You are not developing a healthy eating habit. You are not learning about nutritional informations of your food. Instead, you are tagging some food as "bad" and other food as "good". That means that in the real world you will always have a food obsession and this makes very difficult for a sustained diet.

In conclusion, ketogenic diet represents an emergency mechanism the body has to survive when he's lacking nutrients. In my opinion, nobody should undertake such a treatment without strict supervision of an expert. It is NOT the adequate diet to follow on your own.
It all comes to a risk / benefit estimation , as usual in evidence based medicine. Does a healthy person really need to go into ketosis and undertake these risks to lose weight?
Let's not forget that ketogenic diet has been developed not for weight loss, but for treating epilepsy.

If you really want to try it, I highly suggest you to consult your physician before undertaking such diet restrictions.

Personally, I would not do that to my body just to lose weight.

Ludwig, DS, Majzoub AJ, Al-Zahrani A, Dallal GE, Blanco I, and Roberts SB. “High glycemic index foods, overeating, and obesity.” Pediatrics 103: e26 (1999)

Ebbeling CB, Swain JF, Feldman HA, Wong WA, Hachey DL, Garcia-Logo E, and Ludwig DD. “Effects of dietary composition on energy expenditure during weight loss maintenance.” JAMA 307: 267-2634 (2012)

Johnston, C.S., Tjonn, S., Swan, P.D., White A., Hutchins H., and Sears B. “Ketogenic low-carbohydrate diets have no metabolic advantage over nonketogenic low-carbohydrate diets.” Am J Clin Nutr 83: 1055-1061 (2006)

Agus MSD, Swain JF, Larson CL, Eckert EA, and Ludwig DS. “Dietary composition and physiologic adaptations to energy restriction.” Am J Clin Nutr 71:901–907 (2000)

White AM, Johnston CS, Swan PD, Tjonn SL, and Sears B. “Blood ketones are directly related to fatigue and perceived effort during exercise in overweight adults adhering to low-carbohydrate diets for weight loss: A pilot study.” J Am Diet Assoc 107: 1792-1796 (2007)

Pereira MA, Swain J, Goldfine AB, Rifai N, and Ludwig DS. “Effect of low-glycemic diet on resting energy expenditure and heart disease risk factors during weight loss.” JAMA. 292: 2482-2490 (2004)

Ebbeling CB, Leidig MM, Feldman HA, Lovesky MM, and Ludwig DS. “Effects of a low–glycemic load vs. low-fat diet in obese young adults”. JAMA 297: 2092-2102 (2007)

Turner Z, Kossoff EH. The ketogenic and Atkins diets: recipes for seizure control . Pract Gastroenterol. 2006

DatMurse · June 2013

I also dont think they have evidence on the long term effects being on a ketogenic diet eiither

PhantomMidnight · June 2013

Very informative, thank you for posting this.

bumblebums · June 2013

Juzaam, may I ask what your medical specialty is?

NVM, read in your profile that you are a radiologist

High protein intake: friend or foe? Evidences

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