AMA #2: Protein myths and negative calorie foods

Welcome to the second in an ongoing series of Ask Me Anything posts, where I take questions from friends, readers, and the internet at large and do my best to answer them. While I’m happy to answer literally anything1With the caveat that my answer may be “I don’t know” or “I don’t want to share that publicly.”, I tend to pick things that I’m uniquely suited to answer, require some digging into the literature, or are commonly misunderstood — I figure you can go anywhere to learn how to do a perfect bodyweight squat or read reviews about the best suitcases.2That being said: rollers over spinners, no plastic-sided hard cases, and most Sunday-Thursday travelers don’t need to drop a grand on a Tumi or Rimowa. Travelpro tends to be the best intersection of quality and price, Briggs and Riley is a nice upgrade option.

Question one: protein and nutrient timing myths

I’ve heard so many things about protein — getting enough, getting too much, the importance of post-workout protein, eating it in a bunch of meals being better, eating it all in one big meal being better. What’s the real answer here?

This is actually a synthetic question that I Frankenstein’d together from a variety of questions I’ve gotten about what I’ll generally call protein and nutrient timing myths.

So, let’s take a brief tour through four of my favorite (interrelated) misconceptions about protein and when you eat it:

  1. You must eat at least one gram of protein per pound of bodyweight or your muscles will wither and fall off.
  2. Contradicting the above, eating more than some (often tiny) amount of protein can damage your kidneys, give you cancer, or some other terrible thing.
  3. There’s an extremely limited “anabolic window” after you work out in which you have to eat a bunch of protein and carbs or your muscles will wither and fall off.
  4. To make it all more complicated, there’s a maximum amount of protein (often 25-40g) you can digest or utilize at one time..

1g/lb of bodyweight

Do you actually need to eat at least one gram of protein per pound of bodyweight—the equivalent of two pounds of lean meat per day for a 200lb guy like me—every day to stay happy and strong and healthy?

Almost certainly not.

There have been a number of studies on the minimum amount of protein one needs for healthy living, and the optimal amount for muscle growth and strength development, which is a higher number, but both are well below 1g/lb.

The real minimum number is closer to 0.8g/kg[0.35g/lb] of bodyweight, or around 70 grams for a 200 pound man — which also happens to be the RDA in the US — and even this has a ‘buffer’ calculation built in3Basically, they looked at nitrogen balance and protein needs in a large group of people, and made the recommendation based on a two-sigma interval, which basically means they took the average maximum amount people needed and then went two standard deviations above that. In principle, this should mean that 0.8g/kg is more than enough for 95% of people., so it’s not like an occasional day of hitting a number lower than this is going to make you keel over and die.

The real optimal number for someone lifting weights is dependent on a few things, but tops out in the range of 1.4–2g/kg[0.6-0.8g/lb] of lean bodyweight, around 120–160 grams for a 200 pound man.

So where did one gram per pound of bodyweight come from? I have a few ideas. That number may actually be correct (or even low) for bodybuilders using anabolic hormones. Their protein needs would outstrip a normal person’s, because the extra muscle synthesis boost from the steroids would also outstrip a normal person’s. The general public love copying the habits and behaviors of elites, even when extenuating circumstances4That is, ‘roids make their needs very different from ours.

Also, nutritional supplement peddlers want you to think you need more protein so you’ll buy protein powder. Shocking, I know. They happen to do a lot of “content marketing” in the space, pushing misleading-but-not-incorrect information into public consciousness (we’ll talk more about this in a second).

But I think ultimately, it’s because the real “max optimal for strength/bodybuilding athletes in all circumstances” number is around 0.8g/lb of bodyweight, and people don’t want to do mental math that’s more complicated than counting. So they round 0.8 to 1, and don’t bother calculating lean bodyweight from total bodyweight5Lean bodyweight or LBM (Lean body mass) is just your bodyweight minus the weight of the fat in your body. A 200 pound person with 20% bodyfat has an easy-to-mental-math 160 pounds of LBM, but a person that weighs 156 pounds at 16.5%, well. A little harder to quickly do in your head. And that’s all assuming you even have an accurate sense of your bodyfat percentage, which almost no one does.

All that being said, 1g/lb is easy to remember and calculate, and there’s really no harm in consuming that much protein — which brings us to our next myth.

Eating too much protein will kill you, or something

Unless you already have kidney damage or disease, it probably won’t.6Even then, it might not. It also won’t leach calcium from your bones.

This pernicious myth comes from a few different places, from what I can tell. Namely,

  • A bunch of poorly-designed epidemiological “food journal” type studies that showed correlations between increased protein intake and things like shorter lifespan, cancer risk, heart disease, having an “innie” belly button,7Not really. this is a joke and an excuse to link to a nice article about why this stuff is normally bunk. and just about anything else you can think of.
  • A poor understanding of relative risk versus absolute risk.

    I don’t want to dwell too much on the first one. Suffice it to say that as someone that regularly deals with investigating stated versus actual human behavior in his day job8Software Design and HCI type stuff, more or less., I don’t trust any study that gathers data by asking people to remember something they did a week ago and write it down. I don’t trust survey-based research methods to figure out how to make a user click on a certain part of a website; I’m certainly not going to use them to understand what foods cause disease.

    There are all sorts of other problems with this sort of epidemiological food science that plenty of other people have covered extensively, including Vox and FiveThirtyEight.

    Even past that, most of these studies demonstrate significant relative risk for whatever cancer or heart condition they claim protein causes, without ever talking about the absolute risk involved, which is a much more important number.

    As an example: according to the WHO9who do good science, not knocking the WHO here., red meat is probably carcinogenic, and consumption of red meat definitely increases your risk of certain cancers, to the tune of 22% increased relative risk between the highest and lowest studied intake. But all that means is there is a significant increase in the relative risk of getting cancer for people who eat an above-average amount of steak and lamb and whatever.

    A person at average risk has about a 5 in 100 chance of getting this type of cancer — it’s one of the most common types — which means that the most you could reduce your absolute risk by never eating red meat is is by 0.55 in 100, to 4.55%. Similarly, the most you could increase it is by 0.55 to 5.55%. This is the most prevalent cancer I could come up with to write about, and the absolute risk difference between the lowest and highest incidence is pretty small. For most other examples you could think of, it’s even more miniscule — a 20% increase in something that happens to one in 100,000 people rounds down to “still basically 1 in 100,000.”

    In running the numbers, and including the cost-benefit of quality of life versus length of life and the fact that that higher protein intakes correlate with greater muscle mass and reduced risk of sarcopenia and osteopenia (which both also increase the chance you’ll die), I’ll eat the meat.

    That said, this is not one of those more is more situations — just because it doesn’t hurt you to eat more than the recommended amounts above, you don’t get more benefit by eating more protein, just a more expensive and often less exciting source of energy than whatever carbs or fats you enjoy eating; you probably don’t even get satiety benefits (a common claim) unless you were chronically undereating protein beforehand.

    The anabolic window

    The myth of the anabolic window basically says that you have to get some amount of protein in your body within some amount of minutes after working out or you might as well have just sat on the couch instead.

    It’s a misconception, mostly perpetuated by supplement companies and poor understanding of research.

    Two fairly recent research reviews and meta-analyses of protein (and general nutrient) timing by Brad Schoenfeld and Alan Aragon, both titans of the space10Aragon is a titan of the science, at least — unfortunately all signs point to him also being a sex creep and generally lousy human being. Still, bad people can do good science and that review is worth reading., confirm this: one, two.

    I encourage you to read them both and draw your own conclusions, but the basic summary is “it might help, it definitely doesn’t hurt, it’s almost certainly longer than traditional fitness advice would suggest; a few hours at minimum and even longer if you eat a large mixed meal beforehand.”

    In any case, the effect magnitude of doing this versus not doing this, assuming otherwise adequate protein throughout the day, seems to be pretty small. I wouldn’t go quite so far as to say “it doesn’t really matter when before or after a workout you eat your protein,” but I’d happily say “it doesn’t really matter much, and you should focus on getting adequate total protein before worrying too much about when you get it.”

    35 grams per sitting or it’s a waste

    The research on this is a little scarce, but based on what’s out there, I’ll very confidently say you’re almost certainly not wasting the protein if you eat more than 35 grams at a time.

    For one thing, that’s just not how digestion works. Your intestines have a maximum rate at which they can absorb protein, yes, but your body is smarter than that. It’s able to regulate the speed at which chyme (the chewed up food goo) moves through the stomach into the small intestines to ensure it can absorb all of the available nutrients. If it detects protein in the stomach, it actually slows passage. Specific proteins even have different slowing rates, which actually lends some credence to the “whey is a ‘fast’ protein powder, casein is a ‘slow’ protein powder” thing you hear all the time in bodybuilding circles.

    Past that, we also know that excess protein doesn’t get wasted.

    Sure, it might not be maximally anabolic (that is, tissue-growing) to eat more than ~35g of protein each meal. In fact, it’s almost certainly not, given the anabolic window stuff I just went over. The best way to maximize muscle growth probably is to eat a bunch of small mixed meals throughout the day, like bodybuilders normally do.

    But, there also seems to be no catabolic (tissue-wasting) effect to eating all of your protien in one go. Which is to say, your body is still using the protein effectively to repair tissue and support life, just not necessarily at an optimal rate for muscle growth.

    Two studies to look at for this one: in young women, just looking at protein, one in lean men, looking at an intermittent-fasting diet, including protein. In both cases, they find no detriment to total protein turnover or nitrogen balance; which is to say, no one is losing muscle by only eating one meal a day.

    Unless you’re a competitive bodybuilder AND your diet is otherwise pristine, the behavioral implications of having to eat every few hours (if it’s easier for you to not do that) are considerably more valuable than the relatively small difference in total anabolic effect.

    I can even tell you where that magic 35g number comes from. It’s the top range of 20-40g, the acute amount of protein required to produce a maximal anabolic effect in one dose post-workout. (see: this article and this one; Aragon and Shoenfeld also mention this number in the conclusion of one of their articles). 20-40g is, if anything, a minimum per meal, not a maximum.

    The larger point is: total protein is still king, and it’s valuable to focus on that before meal frequency and timing unless you’re truly in the top 99% of people already. You might be leaving some gains on the table, but the behavioral benefit of being able to more consistently do this at all beats out the small anabolic benefit every time (to say nothing of people who are trying to lose weight).

    If it’s easier for you to do that in a bunch of small meals, do that. If it’s easier to do it in two, or three, or even one, do that. The good system that works for you is always better than the “perfect” system that’s too hard for a busy or otherwise distracted person to actually accomplish.

    Question two: Negative calorie foods

    Is there really such a thing as negative calorie food? Like, I’ve heard it burns more calories to eat and digest celery than you actually get back out of it.

    No. Nothing—except maybe very cold water11And even then, it has such a miniscule impact that it’s not likely to be the cornerstone of anyone’s long-term body composition strategy.— has negative calories.

    But this is another one where the source of the myth (or at least, my guess as to the source) is interesting and enlightening in its own right.

    Basically, when people say that “it costs energy to eat and digest food,” they’re talking about a quality that nutrition scientists call the Thermic Effect of Food, or TEF. All food items have a different TEF, ranging from a few percent of the total calories for something like a highly-refined oil, to almost 30% for certain lean proteins.

    That said, nothing has a TEF greater than 30%, and certainly not greater than 100%. Our biology is just too good at keeping us alive and well-stocked for winter to allow something so foolish.

    But of course, these “negative calories — eat as much as you want!” food lists still prevail, some people swear by them. So What gives? Well everything on these lists are just high-fiber, low-calorie fruit and vegetables. It’s practically difficult to eat a calorically meaningful amount of a food like this, even if you go 100% hog wild on the stuff.

    So, the trick of “negative-calorie” food is that it’s actually “negligible calorie food.” Celery, just to stick with the example, contains a whopping 75 calories per pound.12It’s basically crunchy water. So even at a small 10% TEF, with 67.5 calories being used for energy, you’re just not going to be able to eat a calorically significant amount of celery. Eat three whole pounds and you’re around 200 calories of nutritionally-valuable calories — less than a normal-sized bag of M&Ms.

    Now, pounds upon pounds of celery isn’t what I’d call a cornerstone of a nutritious, balanced approach to eating, and certainly isn’t “negative calories,” but practically speaking, you probably can eat as much as you want of the stuff, because you’ll run out of room long before you make a dent in your calorie budget.

    That’s all for this installment. Want to ask a question for the next mailbag? Send it to ama at roadwarrior dot blog.

    Oh, and as a special bonus disclaimer, even though we say this in the sitewide disclaimers and disclosures: the above is for informational purposes only. While I do my best to be accurate and reasonable in what I say, I’m not a doctor or a dietician — just a curious business traveler with a certification in strength and conditioning coaching and paid access to journal articles. Please consult with a licensed medical and/or nutritional professional before making big changes to the way you eat.

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