Is there such a thing as too much protein?

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Vain_Witch
Vain_Witch Posts: 476 Member
in Food and Nutrition
I had dinner with some friends the other night and one of them is VERY opinionated about weight loss. He was telling me that I'm eating too much protein and this is probably what's slowing down my progress.

Personally, I find that carbs don't do great things to my body, so I've been trying to strive for 40% protein and 30% each of fat and carbs. Some days I'm closer to 50% protein.

He told me that that's too much protein for someone trying to lose weight and that's only useful if I'm a man trying to bulk up. His suggestion was that I bulk up to at least 40% carbs since that is what you burn through first with cardio...

Is he right? Is this too much protein? Or is this just another in a long line of people's opinions that I should ignore? lol

Replies

  • Matt_Wild
    Matt_Wild Posts: 2,673 Member
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    He is talking rubbish.

    Diets higher in protein are less “energy efficient” as the conversion of alanine to glucose during gluconeogenesis (production of glucose from amino acids and other substrates) requires 6 ATP molecules and the conversion of pyruvate to glucose also consumes 6 ATP molecules (2-3). Furthermore, 4 molecules of ATP are required to dispose of the nitrogen as urea (3). Now before you throw up your hands and say “what the hell does all that mean?” realize that it’s only a scientifically correct way of saying that turning protein into energy requires more energy input by your body compared to carbs or fats. Maintaining the protein turnover is also energetically very costly (4). In fact, the thermic effects of nutrients are approximately 2-3% for lipids, 6-8% for carbohydrates, and 25-30% for protein (5)!


    2) Feinman RD and Fine EJ. A calorie is a calorie violates the second law of thermodynamics. Nutrition J. 2004, 3:9.
    3) Hue L. Regulation of gluconeogenesis in liver: In: Jefferson L, Cherington A, eds. Handbook of physiology: the endocrine system. Vol 2. Oxford, United Kingdom: Oxford University Press, 2001:649-57.
    4) Bier DM. The energy cost of protein metabolism: lean and mean on Uncle Sam’s team. In: The role of protein and amino acids in sustaining and enhancing performance. Washington, DC: National Academies Press, 1999:109-19.
    5) Jequier E: Pathways to obesity. Int J Obes Relat Metab Disord 2002, 26 Suppl 2:S12-7.
  • TR0berts
    TR0berts Posts: 7,739 Member
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    Your friend has no clue what he is talking about. Ignore him completely. Protein is "good" in that it helps your satiety, meaning you're less likely to overeat.


    That's in addition to what Matt just posted.

    Unless you're eating upwards of 300g of protein, you're fine. I just took a look at a few days of your diary. Your protein intake is fine.
  • Vain_Witch
    Vain_Witch Posts: 476 Member
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    Ok...excuse my Monday morning brain...that means that more protein is good because my body has to work harder to turn it into the energy that I'm going to use for my workouts? Or it's bad, because I need to expend more energy to burn through the protein?

    Sorry...just trying to understand...Science was never my strong point! lol
  • lumstead0317
    lumstead0317 Posts: 85 Member
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    It's only a problem and hindering your weight loss if you're not getting fiber also... in turn not pooping! I do think you can have too much protein, but I def think that's very hard to do! (You can drink too much water so I'm sure you can have too much protein!)
  • Matt_Wild
    Matt_Wild Posts: 2,673 Member
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    Ok...excuse my Monday morning brain...that means that more protein is good because my body has to work harder to turn it into the energy that I'm going to use for my workouts? Or it's bad, because I need to expend more energy to burn through the protein?

    Sorry...just trying to understand...Science was never my strong point! lol

    To turn a calorie into energy it loses 25-30% of its calorie value meaning it wastes energy having more protein in diet. Wasted energy means less spare energy stored back as fat.

    It also means you can hold lean muscle for protein that is not converted to energy.
  • juu4
    juu4 Posts: 2 Member
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    http://en.wikipedia.org/wiki/Protein_(nutrient)#Excess_consumption

    I think anything up to 2 grams of protein per day per kilogram of weight should be completely fine. If you go above that, then it is also likely fine, but at least then the question makes sense.

    But I guess I will find out, I'm at 2 - 2.5 g per kilogram for a few years now.

    P.S. Just because someone's opinionated doesn't make him knowledgeable. Usually vice versa.
  • Vain_Witch
    Vain_Witch Posts: 476 Member
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    Gotcha! That makes more sense! Thanks! :)

    Really? You can have too much water?? I KNOW I'm nowhere near that problem...I have to forcefeed myself water. lol I never knew that, though!
  • Matt_Wild
    Matt_Wild Posts: 2,673 Member
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    Also, this shows safety up to 2.8g/kg body weight:

    Do regular high protein diets have potential health risks on kidney function in athletes?
    Poortmans JR, Dellalieux O.
    Source
    Department of Physiological Chemistry, Institute of Physical Education and Kinesiotherapy, Free University of Brussels, Belgium.
    Abstract
    Excess protein and amino acid intake have been recognized as hazardous potential implications for kidney function, leading to progressive impairment of this organ. It has been suggested in the literature, without clear evidence, that high protein intake by athletes has no harmful consequences on renal function. This study investigated body-builders (BB) and other well-trained athletes (OA) with high and medium protein intake, respectively, in order to shed light on this issue. The athletes underwent a 7-day nutrition record analysis as well as blood sample and urine collection to determine the potential renal consequences of a high protein intake. The data revealed that despite higher plasma concentration of uric acid and calcium, Group BB had renal clearances of creatinine, urea, and albumin that were within the normal range. The nitrogen balance for both groups became positive when daily protein intake exceeded 1.26 g.kg but there were no correlations between protein intake and creatinine clearance, albumin excretion rate, and calcium excretion rate. To conclude, it appears that protein intake under 2. 8 g.kg does not impair renal function in well-trained athletes as indicated by the measures of renal function used in this study

    http://www.ncbi.nlm.nih.gov/pubmed/10722779

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