It's really hard to talk nutrition with someone, especially when you stick to the science and they can throw out sentiment after sentiment - sentiment always sounds better than science! Here's a few common sentiments I get all the time that are so far from scientific:
1. "But so and so did it and lost a ton of weight!" - This one's from the people who never took a statistics course. 'Miley Cyrus went gluten-free and look how healthy she is!!' is known as an n=1 situation - one person's experiences don't say much, and nothing controls for confounding factors. If we took every anecdote of healthy people, whether they were olympic athletes or individuals who lost 400lbs, we'd get about 100+ diets out of it (go look at the diet section of your local book store - I'd say about a 100). What one person did to stay healthy only shows the dietary plasticity of the human body - we can eat a variety of things, or not eat a variety of things, and be healthy! Not to mention weight loss isn't a great measure of overall health. As we known from studies of centarians, they love to smoke, drink and not exercise (1) - that doesn't mean we should go recommending it to the masses!
2. "We didn't evolve to eat it!" - this one kills me. for a lengthier post on this, see here. In short, evolving to eat something simply means it allowed humans to survive to the age of reproduction. If it helped you live to have sex and reproduce, you evolved to do it. Evolving to eat something means nothing about enhancing longevity, quality of life or deterring chronic disease. Seeing as most of America's nutrition-related woes are found in post-reproductive ages, why are we still talking about what we evolved to eat? Don't get me wrong, actual evolutionary genomics can probably point of us in directions of where to look for selection and genetic variance related to nutrient needs, but evolutionary theorizing (often leading people to overemphasize selection relative to drift/mutation/flow and culture/technology) doesn't hold a place in science-based recommendations.
3. "There's no dietary requirement for it" - I hear this in relation to dairy/grains all the time. "We don't need to eat them." And they're absolutely right, you don't need to eat grains. You also don't need to eat dairy, you don't need to eat legumes, you don't need to eat nuts, you don't need to eat meat, you don't need to eat kale, you don't even need to eat fruits. Hospitals keep people fed with mixes of glucose and isolated vitamins and minerals - you need nutrients. No you don't need to eat grains - but you do need to eat calories, magnesium, manganese, selenium, B-vitamins, vitamin E, and fiber. If you choose to not get those nutrients from grains, that's fine - but the argument is not a valid reason to eat or not eat something. Get your nutrients.
4. "I removed 'x' from my diet and all my symptoms cleared up!" - Back to #1, in these situations n=1. It's fine if you feel better after eating something and you see some physical change (example: some individuals swear dairy clears their acne, some swear it does nothing)- you don't necessarily need to eat it, but you may need to augment your diet to get those nutrients, and encouraging others to displace those nutrients may be unfounded. This argument is more problematic when someone says "I went paleo/gluten free/vegan/lowcarb and all of my ailments went away" - often times I hear this from people who were severely overweight, started losing weight, drastically increased their fruit and vegetable intake, ate more fiber and omega 3's, less simple starches/sugars, and in general, a more nutrient dense diet - at the end of the day, though, they tell everyone going gluten-free or not eating animal products cleared up all of their ailments. Talk about confounding factors....
5. "No other species eats it, so we shouldn't" - This one I really only hear in relation to dairy, and raw food. There's a difference between no other species eats it, and no other species has systematically enslaved another species to consistently steal it's milk... Your cat isn't going to be able to have the ability to milk a cow, but I guarantee you if you put a saucer of cow's milk in front of it, it will drink it. Same goes for raw food - other species don't have fire - but that doesn't mean if you give cooked sweet potatoes to monkeys/primates, they won't love it. People need to stop thinking of food as a food, and more as a vehicle for nutrients - surely, some people can't consume (allergies, intolerances, inborn errors of metabolism) other parts of that nutrient vesicle, and even some of the nutrients - but all foods have biochemical similarities - they provide calories/fat/protein/carbs. Agriculture brought about the introduction of dairy foods into our society, yes, but it also brought about a number of domesticated plant species, and exotic fruits most people, or their ancestors, never consumed - very novel foods, arguably more novel in human history than dairy - but no one is questioning eating domesticated plants and tasty fruits.. This isn't to say that some foods aren't more optimal than others for certain individuals, depending on their genotype/epigenotype/microbiome - but until those studies are complete, show me the evidence that humans shouldn't eat dairy or cooked food. If you choose not to eat these foods for environmental or ethical reasons, that is fine - but relying on invalid philosophies will only hinder the progression of your movement.
1. http://onlinelibrary.wiley.com/doi/10.1111/j.1532-5415.2011.03498.x/full
1. "But so and so did it and lost a ton of weight!" - This one's from the people who never took a statistics course. 'Miley Cyrus went gluten-free and look how healthy she is!!' is known as an n=1 situation - one person's experiences don't say much, and nothing controls for confounding factors. If we took every anecdote of healthy people, whether they were olympic athletes or individuals who lost 400lbs, we'd get about 100+ diets out of it (go look at the diet section of your local book store - I'd say about a 100). What one person did to stay healthy only shows the dietary plasticity of the human body - we can eat a variety of things, or not eat a variety of things, and be healthy! Not to mention weight loss isn't a great measure of overall health. As we known from studies of centarians, they love to smoke, drink and not exercise (1) - that doesn't mean we should go recommending it to the masses!
2. "We didn't evolve to eat it!" - this one kills me. for a lengthier post on this, see here. In short, evolving to eat something simply means it allowed humans to survive to the age of reproduction. If it helped you live to have sex and reproduce, you evolved to do it. Evolving to eat something means nothing about enhancing longevity, quality of life or deterring chronic disease. Seeing as most of America's nutrition-related woes are found in post-reproductive ages, why are we still talking about what we evolved to eat? Don't get me wrong, actual evolutionary genomics can probably point of us in directions of where to look for selection and genetic variance related to nutrient needs, but evolutionary theorizing (often leading people to overemphasize selection relative to drift/mutation/flow and culture/technology) doesn't hold a place in science-based recommendations.
3. "There's no dietary requirement for it" - I hear this in relation to dairy/grains all the time. "We don't need to eat them." And they're absolutely right, you don't need to eat grains. You also don't need to eat dairy, you don't need to eat legumes, you don't need to eat nuts, you don't need to eat meat, you don't need to eat kale, you don't even need to eat fruits. Hospitals keep people fed with mixes of glucose and isolated vitamins and minerals - you need nutrients. No you don't need to eat grains - but you do need to eat calories, magnesium, manganese, selenium, B-vitamins, vitamin E, and fiber. If you choose to not get those nutrients from grains, that's fine - but the argument is not a valid reason to eat or not eat something. Get your nutrients.
4. "I removed 'x' from my diet and all my symptoms cleared up!" - Back to #1, in these situations n=1. It's fine if you feel better after eating something and you see some physical change (example: some individuals swear dairy clears their acne, some swear it does nothing)- you don't necessarily need to eat it, but you may need to augment your diet to get those nutrients, and encouraging others to displace those nutrients may be unfounded. This argument is more problematic when someone says "I went paleo/gluten free/vegan/lowcarb and all of my ailments went away" - often times I hear this from people who were severely overweight, started losing weight, drastically increased their fruit and vegetable intake, ate more fiber and omega 3's, less simple starches/sugars, and in general, a more nutrient dense diet - at the end of the day, though, they tell everyone going gluten-free or not eating animal products cleared up all of their ailments. Talk about confounding factors....
5. "No other species eats it, so we shouldn't" - This one I really only hear in relation to dairy, and raw food. There's a difference between no other species eats it, and no other species has systematically enslaved another species to consistently steal it's milk... Your cat isn't going to be able to have the ability to milk a cow, but I guarantee you if you put a saucer of cow's milk in front of it, it will drink it. Same goes for raw food - other species don't have fire - but that doesn't mean if you give cooked sweet potatoes to monkeys/primates, they won't love it. People need to stop thinking of food as a food, and more as a vehicle for nutrients - surely, some people can't consume (allergies, intolerances, inborn errors of metabolism) other parts of that nutrient vesicle, and even some of the nutrients - but all foods have biochemical similarities - they provide calories/fat/protein/carbs. Agriculture brought about the introduction of dairy foods into our society, yes, but it also brought about a number of domesticated plant species, and exotic fruits most people, or their ancestors, never consumed - very novel foods, arguably more novel in human history than dairy - but no one is questioning eating domesticated plants and tasty fruits.. This isn't to say that some foods aren't more optimal than others for certain individuals, depending on their genotype/epigenotype/microbiome - but until those studies are complete, show me the evidence that humans shouldn't eat dairy or cooked food. If you choose not to eat these foods for environmental or ethical reasons, that is fine - but relying on invalid philosophies will only hinder the progression of your movement.
1. http://onlinelibrary.wiley.com/doi/10.1111/j.1532-5415.2011.03498.x/full
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