Can You Spot These 7 Broken Nutrition Arguments?


Recently, I posted an article explaining why I am a vegetarian. The bulk of the article hinged on the ample nutritional evidence that, if not the best diet, vegetarianism was at least better than most.

Since posting that article, I’ve had a number of comments that countered my claims with different nutritional arguments. Unfortunately, it’s easy to rely on nutritional arguments that aren’t logically sound. I think these broken arguments are part of the reason people are so generally confused about what to eat.

First, let me explain that I’m strictly an amateur when it comes to nutrition. I’ve never taken a formal course, so all of my knowledge comes from a passion in the topic causing me to read more than a dozen books and hundreds of articles.

But, you don’t need a degree in nutritional science to spot flawed arguments. Most of these fallacies are easy to spot with a little common sense, despite being used frequently to promote one diet or another. While spotting these fallacies won’t tell you exactly what diet is best, it does sensitize your bullshit meter for flawed reasoning.

#1 – If It’s Good for Weight Loss, It’s Good for Health

It doesn’t take much brainpower to see the flaws in this argument. You could also lose weight by sawing off one of your legs, that doesn’t mean it’s a great health strategy.

However, frequently I see comparisons being made that demonstrate that because a diet causes weight loss, it’s also a healthy diet. True, being obese increases your risks for many diseases, so all else being equal, being skinnier is probably better for your health. However, all else isn’t equal, and losing weight isn’t the barometer for health.

#2 – If Our Ancestors Ate It, It’s Good for Health

This one works on the evolutionary argument, and it’s more difficult to see where this argument breaks down. The difficulties lies in that the argument does make sense at some level. It simply breaks down when it is applied to a logical extreme.

The flaws in evolutionary reasoning are simple. If a type of diet (let’s say one that favors more protein) had even a small advantage during a caveman’s twenties, that would outweigh even disastrous consequences later in life.

For example, if a diet caused cavepeople to drop like flies in their sixties and seventies (as many degenerative diseases  will do) but it allowed younger cavemen to be slightly stronger, that diet would persist within the evolutionary lines. But, now in the 21st century where being slightly stronger isn’t worth dying 20 years earlier, the traditional diet no longer serves our needs.

I’m not saying evolutionary arguments are completely useless, just that you can’t take them to an extreme. Vegetarians and carnivores both love pointing out evolutionary justifications for their particular diet, so be skeptical first.

#3 – If I Have More Energy, It’s Good for Health

This is an anecdotal argument where a particular person raves about the extra energy they have from eating a particular diet. The problem here, of course, is that the placebo effect is strong. Especially with qualities as subjective as energy levels.

If you feel more energized after a diet switch, that’s great. Just realize that some (or potentially all) of that effect might be from taking the initiative to change your diet. And, if someone tells you they feel great after a diet, try to find some objective research to back their claims before swallowing it wholeheartedly.

#4 – If It Contains More of Nutrient XYZ, It’s Good for Health

Science loves reductionism, breaking down nutrition into specific nutrients. Unfortunately, as has been argued by nutritional experts such as Dr. Colin Campbell and has even been made the subject of a bestselling book by Michael Pollan, reductionism has limits.

Just because a substance contains more Omega 3s, that doesn’t make it healthier. Nutrition is a complex relationship between many different nutrients, and linear addition of different components doesn’t work. As an example, Omega 3s and Omega 6s work on a balancing scale, so eating more Omega 3s reduces your Omega 6s and vice-versa. So simplistic arguments that claim a certain food item is good because it contains XYZ are bogus.

#5 – If It’s Low in Dangerous Toxin XYZ, It’s Good for Health

This is just the converse of the last fallacy. Just because something is low in sodium, does not make it healthy for you. This is a fact many food marketers hope you’ll forget when they happily label there unhealthy processed foods as health items because they are “Contain Zero Trans-Fats!” or “Low in Cholesterol!”

#6 – If Healthy People Eat It, It’s Good for Health

Correlation is not causation. Just because native inhabitants from a lonely island of Japan live to 95 eating a particular diet doesn’t mean it is healthier. Different lifestyles have thousands of different potential causes, including genetics, differing lifestyles and cultural influences.

If people die when they switch to a diet, typically, that’s a good sign it isn’t healthy. But don’t overextend correlation arguments used to explain the nutritional power of a particular way of eating.

#7 – If It Made Rats Healthier, It’s Good for Health

Many nutritional experiments involve giving rats a particular diet or nutrient in extremely high doses and watching what happens. While this has some usefulness in gauging hypotheses or pushing further research, it doesn’t translate to human nutrition.

First of all, humans aren’t rats. Second, humans don’t eat nutrients in sterile laboratory environments in extreme quantities, so the implications of feeding a mouse 20,000x the level of a particular carcinogen and observing cancer isn’t entirely relevant to human nutrition.

What Arguments Can You Rely On?

With most of the above arguments, there are weak spots in their logic. That doesn’t mean they shouldn’t have any persuasive power, just that they shouldn’t be relied on entirely. If a diet causes weight loss, that’s a better sign it’s good for health than if everyone who eats it becomes fat. If a diet killed rats instantly, that’s a better sign it should be avoided in humans.

The best arguments are based on experimental evidence. Particularly those which use a large sample of people and test conditions similar to how people actually consume food. Naturalistic experiments, which use large populations of people changing diets, are also a better alternative.

If someone tells you that in a large, controlled research environment that people who switched to the diet typically saw their health increase, I would put more emphasis on that than the evolutionary rants of a dietary zealot or the magic healing benefits promoted by a blogger.

Why does this matter? Well, whether you understand the confusing sea of nutritional info or not, it’s still your body and you’re the one who has to live in it.

  • Rob

    You forget “If it’s natural, it’s good for health.” I see this one in advertising all the time, but there are plenty of natural foods that are not healthy.

  • Armen Shirvanian

    Reading point #3, it seems about right. I was telling people I was getting even more energetic by drinking more water regularly, but I’m pretty energetic on the whole. There is probably a placebo effect when I tell some folks about how my eating or exercising habits affected my attitude.

    I like pointing out how to have more energy to others, so that might be part of it.

  • Scott Young


    Definitely. I tried to focus on the narrower, and more sophisticated, argument of traditional diets that fools more people than the “it’s natural!” bluff, but you bring up a good point.


  • Jeff

    Hi Scott,

    We don’t share the same diet, but I agree with the points in this article.

    I eat mostly meat, high [saturated] fat, low carb — a general “paleo” approach. The Paleo diet argument is a bit more subtle than just “our ancestors did it, so we should do it too”. It’s more accurate to say that the paleo diet is based on an intuitive hypothesis, but it’s just a hypothesis. The real scientific arguments come from careful comparisons between modern and ancient diets, and their respective development of disease.

    All I have left to say is that even in the face of strong, sometimes obvious intuition, science has a history of surprising us with unexpected truths — e.g. Physics in the 20th century.

  • Vlad Dolezal

    Funny you mention #3 Scott, I actually switched to vegetarianism after hearing from you and Steve Pavlina that it made you more energetic and clear headed.

    I didn’t notice anything like that. Then again, it’s been about 8 months, and I haven’t had much trouble with my vegetarianism, so I’m keeping it up for now. Maybe I really AM more clearheaded and just didn’t notice.

    (completely unrelated: I’m on day 14 of my 30-day trial of writing at least 500 words every day. Never made it this far before. Thanks for writing “How to Change a Habit”!)

  • Dave

    As another paleo-eater (I hate that term). I would recommend that you read more in depth into a paleolithic style diet. Most paleolithic peoples and modern tribesmen that still follow such a way of life often live into their sixties. The common cause of death still remains the hunting accident. For the record, I am a nutrition major with the intention of becoming a registered dietitian.

    Now from an ecological standpoint, I support vegetarianism. But in classic tragedy of commons fashion, I refuse to do what I believe would sacrifice my own well being only to not make so much as a dent in the ecological impact of livestock.

  • Scott Young

    Dave and Jeff,

    I’m actually surprisingly ignorant on the paleo diet, so I can’t comment on it’s efficacy.

    My comment on ancestral diets comes from a lot of vegetarians (and omnivores) explaining how the human digestive system is designed to only handle a particular type of food because (theoretically) that’s how early humans ate. I think this type of reasoning is useful when excluding likely unhealthy foods (such as potato chips) but it isn’t as useful when selecting the ideal diet.


    I’m not saying you should completely dismiss thoughts about higher energy levels, just that shouldn’t be your only go-to point when making a diet change. I also read about Steve Pavlina’s success with the diet, and backed it up with reading a few scientific books to make sure he wasn’t completely crazy.


  • Jeffrey

    I was introduced to paleo through Crossfit (which I brag is the best workout program ever). What is cool about the Crossfit recommended diet is the fact that they combine paleo with The Zone so you control your portions, eat often, and stay paleo with your choices.

    I like the ethical implications of being vegetarian, but I’m still not sold on the health implications. It seems to me that every diet has ups and downs. Like you mention the evolutionary portion, you could use this argument against some of your own points. I’ll be it you tried hard enough, you could make an argument against vegetarianism.

    It’s like being on debate team. You could argue both sides with efficacy.

  • Will

    Diet is a very emotional topic for everyone. I don’t think anyone has “the answer”.
    We do know that a) genes are on/off switches for producing proteins, and that b) at this point in time, the body is a bit of a black box.
    We know if we control certain inputs, we can turn some switches on and off, and they have some measurable effect.
    How this affects us on a day to day level (and long term) is probably a little different in the real world than in a lab experiment.

    At the end of the day, people will do what works for them, and fits their needs. I’ve experimented with several diets, and I feel I was disciplined about it.
    If you’re a power athlete, it’s highly unlikely you’re on a vegetarian diet. (Although I think some people respond better to a vegetarian diet than others, but perhaps they also have different physical activity levels. When I went through my vegetarian stage, it amazed me how often people in the health food stores looked so wan, soft…basically unhealthy. ps-if you’re vegetarian, this comment is NOT about you, I mean the other people)
    But if it works for you, and you’re not eating junk food, you’re a lot better off than the average person.

    I think this a well thought out review to “The China Study”.
    I think Dr Campbell had good intentions, but his methodology and conclusions were flawed. And if you actually spent any time in China, you’d know they are not anywhere near vegetarian. There is no indigenous culture anywhere that is vegetarian.

    This NYTimes article is also a decent primer about your endocrine system and low-carb/high-carb diets :

    There seems to be a few Crossfitters on this blog. I basically do a paleo diet as well, but by no means can I be certain that this is optimized for health, longevity, strength, or whatever, especially over a 60+ year period. (I think the French seem to do just fine, and they seem to love their fats, baguettes and wine)
    This applies to any diet, because there has been NO controlled experiments of that sort, and to my knowledge probably won’t be anytime soon because it would cost a ridiculous amount to fund such a large scale study.

  • Jeff

    Hi again,

    I hesitate to make this comment, but will do so anyway.

    There’s a book that many readers here might find valuable — The Vegetarian Myth by Lierre Keith. There’s a reasonable review of it here:

    Recommending a book called “The Vegetarian Myth” to a group of veg-sympathetics is a bit like recommending The God Delusion to a group of Christians.

    But I assure you the book is not about picking fights with vegetarians. It’s a bit of an unfortunate title, because the book really explores some of the subtleties behind vegetarian dogma.

    You hear a lot about the ecological benefits of vegetarianism, but ecology is not so simple. Every decision we make has an infinite series of cascading consequences.

    (Like how you wouldn’t be here if your great-great-great-great-great-great-great-great grandparents didn’t meet after a series of synchronistic events.)

    The ecological/moral impact of eating agrarian foods is a lot more complicated than we think. A field of grains is responsible for the death of countless animals during the harvesting process, the deaths of numerous bacteria — and quite simply, the death of entire acres of habitable land.

    Grains kill ecosystems.

    I want to puke every time I hear Mr Pavlina meat eaters don’t feel moral remorse for animal murder because the act is “out of sight”, therefore “out of mind.” I eat a cow, and am thus at a single degree of separation between the death of that cow. But eating grains and other agrarian foods puts you 2-3 degrees away from the deaths of infinitely more organisms. Out of sight, out of mind, eh?

    The more I read about the interconnected, down-cascading consequences of our dietary decisions, the more I think that eating a humanely-treated, grass-fed cow is probably the most ecologically and morally responsible decision we can make.

    Either way, I really don’t have a beef (haha) to pick with anyone, veg or not. Just realize that some of the popular arguments for vegetarianism are sophomoric at best. That doesn’t mean more sophisticated arguments don’t exist. But dig a little deeper before accepting the current dogma.

  • Jeff

    One more note, sorry:

    One reviewer on Amazon for Lierre’s book put it much, much more eloquently than I did in my above comment:

    “Lierre Kieth has been accused of being against veg*ns, but after reading her book I don’t agree. Here’s what I think: She is against industrial agriculture, because agriculture annihilates ecosystems–agriculture is bio-cleansing; it’s killing the Earth, one sterile petro-chemical saturated field at a time. It can’t go on. And because she’s against agriculture she is, by default, against vegetarianism, because vegetarianism can’t exist without the expansive farming of mono-crops. “


  • Scott Young


    No, thanks for posting, I always like a contrasting view.

    I’ve never read the book in question, but I’m extremely skeptical of it’s premise, namely that vegetarian eating supports agricultural mono-cultures and results in a higher net-death of animal life. I’m not saying the book’s premise is incorrect, just suspicious.

    First, in order to factory farm meat, one needs to feed cows, pigs or chickens a lot of mono-culture grains. Sure, some animals are pasture raised, but as Michael Pollan explains so eloquently in The Omnivore’s Dilemma, this is not the case with almost all meat production. So, in order to eat meat, not only are you consuming the cow, but all the 2nd and 3rd degrees of separation away from those monocultures used to support traditional livestock.

    Second, who says you need to eat a monoculture diet while being a vegetarian? I see no restriction that disables a vegetarian from eating a large amount of species, that would somehow be available to a traditional omnivore. Perhaps I’m missing your argument here, but it doesn’t add up from the first glance, maybe you could elaborate it for me.

    Finally, with regards to the animal deaths and ecosystem collapse involved in the mass production of farmland, I have two points:

    1. I agree, there are considerable consequences. However, the practice of organic farming seems to offer only a somewhat better alternative as the restricted growing environments reduce the yields on crops and force foods to be shipped further distances, increasing the impact of fossil fuels.

    2. Unless you hunt your food, or only eat meat from pasture-raised livestock, you’re also buying into the monoculture agricultural paradigm. Cows, pigs and chicken are fed on corn, the highest calorie per acre yielding crop ever invented by humans. So, any problems that occur with animals dying, ecosystem collapse and increased environmental damage would occur to an even higher degree with a meat-based diet (because the amount of input calories of corn, for example, to raise a cow are many times higher than the calories humans derive from it’s meat).

    So, unless I’m missing an important point, I fail to see how, except in highly unique cases, vegetarianism creates the loss of more life and ecosystem destruction than meat eating.


  • Hauke

    Is this a blog of how to get more from life or why or why not to be a vegetarian?

  • Scott Young


    It’s a blog on many topics. As you’ll see from viewing the archives, my discussions of vegetarianism are only in about 3-5 articles of 700. Which means that less than .5% of the content of this blog is aimed at that subject.

    Variety is the spice of life, and my blog.


  • wendell

    Great, informative post…gets right to the main points and states them succinctly. Thanks for sharing!

  • Gordie Rogers

    Hey Scott, first time to your blog. Very interesting post. The one thing I don’t like vegetarians throwing around is the arbitrary moral argument that it’s wrong to kill. Nature is based on killing. Why is it okay to kill plants, but not animals. I’m not aware of any proof of humans having souls, let alone animals.

    Anyway, really enjoyed the post and the intelligent comments of the readers too. I’ll subscribe by RSS. 🙂

  • Scott Young


    I doubt most vegetarians have philosophical views that simplistic.

    First, nature doesn’t equal morality. Humans murdered each other in our natural environment too, but we consider murder unethical.

    Second, the argument isn’t over a “soul” but whether animals can suffer. I’m not going to go into the extreme details, because the actual argument is more complex. But, the moral argument of vegetarianism is whether animals can suffer, and if they do, whether inflicting that suffering for the purpose of food is ethical.


  • hermes handbags

    Hey Scott, first time to your blog. Very interesting post. The one thing I don’t like vegetarians throwing around is the arbitrary moral argument that it’s wrong to kill. Nature is based on killing. Why is it okay to kill plants, but not animals. I’m not aware of any proof of humans having souls, let alone animals.

    Anyway, really enjoyed the post and the intelligent comments of the readers too. I’ll subscribe by RSS.