nutrition · running

some nutrition myths vs fact

“I tried to stay off the internet until we met so you could tell me the right things to do,” said exactly one patient in all of my years as a dietitian thus far. This happened fairly recently so it’s fresh in my mind, and once I got over the initial shock at the novelty of this statement, it look a little restraint to not hug her.

getting lost in the black hole of nutrition-related Googling is just a couple fingertips away from all of us, and if there’s something of personal interest to fuel those searches – a new medical diagnosis, upcoming race, desire for weight loss – it’s easy to believe just about everything we read. I knew dispelling popular nutrition myths would be a part of my job when I became a dietitian, but I had no idea how much (ahh, the innocence). The digital age makes it pretty easy for incorrect information to spread like wildfire. I hear at least a few new and old theories every day, from the sort of fact-based (“I’m eating more beets because they will make me faster”) to the misunderstood (“Sugar feeds cancer”) to the completely crazy (“Someone told me that I have to go for a walk right after eating fruit and it has to be in the morning”). A good deal of my time is spent dispelling advice people have come across that isn’t based on anything other than opinions, individual experience and/or wonky science, and although I have to laugh at some of this stuff, I do take it pretty seriously. A lot of it is not only unnecessary, but it can be harmful and result in nutrient deficiencies, reduced efficacy of important treatments/medications, stress the body systems, lead to disordered eating habits, etc.

here are a few common nutrition-myths that come to mind:

soy causes breast cancer – not true! This is a very general and very misunderstood statement, stemming from the fact that soy naturally contains a plant-based form of estrogen (called a “phytoestrogen”). The assumption here is that these phytoestrogens may act as our own estrogen when we consume soy products, increasing the estrogen in our bodies and the risk for hormone sensitive cancers like breast cancer. But, all of the latest research is dispelling this theory and pointing towards soy products as being beneficial, if anything, for women with breast cancer or those at risk because these phytoestrogens do not act act the same way as our own estrogen. In fact, they may have a protective effect. The caveat here, though, is that this only goes for whole soy products. So, tofu, edamame, soy milk, tempeh, soy yogurts and the like are fine, but processed soy products with unnaturally high amounts of these phytoestrogens may be harmful. These are things like soy-based protein powders or bars, and soy-based vegetarian “meats.” The earlier studies that have linked soy and breast cancer have been conducted on mice who had been given unnaturally high amounts of soy protein isolate, which they metabolize differently in their tiny mouse bodies than we as humans do. This is a good basic resource for more information.


(soy milk is a nice alternative to cow’s milk if you’re sensitive, with just as much protein! works well in oats)

low potassium levels cause muscle cramps – gah! How many times have you been told (or thought you had to) eat a banana to help with muscle cramps? This has never actually been proven, and although electrolyte loss may play a role in heat-related muscle cramping, potassium is not the key player. Sodium is. And even this depends on the individual – salty sweaters are more likely to experience muscle cramping during long endurance events in the warmer months due to excessive sodium losses in sweat. We (I am a super salty sweater!) can be proactive and try to prevent these types of cramps by consuming sodium along with fluids during runs. My favorite way to do this is with Nuun tablets, which contain 360mg of sodium per tablet (and funnily enough, their website states the potassium in the tablets will prevent muscle cramping. Time to update that, guys!). Most gels contain sodium as well, but the amount may vary. No matter what you’re using, it’s always important to check labels and make sure your sports drink/nutrition contains sodium. I’ve seen some runners using coconut water for long runs recently, which is an excellent potassium source but contains little to no sodium (so, no bueno!). Salty snacks before and after the run can also be extremely helpful, and there has even been some recent research on the role of pickle juice in replenishing sodium losses in sweat. Aside from sodium, though, a more common cause of muscle cramps is muscle fatigue, high intensity exertion and insufficient conditioning. The best way to prevent these may be to train appropriately (so don’t run a marathon on little to no training).

organic foods contain more nutrients than non-organic/conventional foods – incorrect! A pretty major study was conducted a few years ago comparing nutrients and health effects of organic vs conventional foods and found no significant difference in nutrient content between the two. This means the vitamin, mineral, antioxidant, protein, etc. content of your favorite fruits, vegetables and animal products is going to be about the same whether they are organic or conventional. There may be a slightly higher omega-3 fatty acid content in some organic animal products – dairy, eggs, chicken, beef – due to the different feed that animals are given, but this difference may not be significant. So what is the difference between organic vs conventional foods, you ask?

organic products are produced using methods that preserve the environment and avoid most synthetic materials, such as pesticides and antibiotics. In the U.S, products MUST meet USDA organic standards in order to be labeled “USDA Organic”. These standards cover the product from farm to table, including soil and water quality, pest control, livestock practices, and rules for food additives. Organic farms and processors:

  • Preserve natural resources and biodiversity
  • Support animal health and welfare
  • Provide access to the outdoors so that animals can exercise their natural behaviors
  • Do not use antibiotics or growth hormones on animals; no genetically modified ingredients
  • Receive annual onsite inspections
  • Separate organic food from non-organic food

so if any of these points are important to you, going organic may be the way to go if you can swing it financially, but don’t be fooled into thinking you’re getting more nutrient bang for your buck. This is a great resource for more info.


(eggs will also not raise your cholesterol!)

among many other topics, I also wanted to mention the alkaline diet here (and how there is no scientific evidence behind its principles) but that is turning out to be a whole different post. So stay tuned!


6 thoughts on “some nutrition myths vs fact

  1. Interesting reading! Good point re: sodium. I sweat like crazy and I’m a salty sweater, so I always make sure to get enough sodium, not only to avoid cramping, but also to avoid dizziness (sodium retains liquids in your body and that way, you stay hydrated – tell me if I’m wrong here). I switched from Gu to Powergel (they have the highest amount of sodium among all gels) and from Gatorade G2 to Gatorade Endurance Formula for this very reason. Even when I buy Clif bars and such, I always make sure to get the ones with the highest amount of sodium. Yes, I’m a bit OCD, but it really makes a difference for me 😉


    1. 🙂 sodium definitely helps your body retain fluids, which is important to keep a proper fluid/sodium balance. but, the most important reason to consume sodium during a run is to replace the salt we lose in sweat, because that affects this balance! I’m with you on the salty sweating and the salty products. After a recent super super hot long run I actually had a few pickles and some pickle juice and felt better IMMEDIATELY. if you like pickles, worth a try!


  2. This was a great lesson for me! I bought coconut water this past weekend at the store to try a different electrolyte source. I didn’t love the taste so this gives me good reason not to buy it again! (I typically use nuun but sometimes I think makes my stomach wonky…)

    On another note, I think I read recently that we don’t need as much protein as has been previously recommended? Would you be willing to elaborate on that?

    (I like your new posts! Very informative!)


    1. thanks Mary! So nice to hear from you again 🙂 I think protein recommendations remain the same for generally healthy people (0.8-1g/kg body weight), with athletes needing a bit more depending on the sport. But, most Americans eat way more than that if they follow a typical “Western” diet or have too many protein shakes, bars, etc. which i think is what the recent news was trying to say.


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