It seems like we’re constantly hearing different things about nutrition: a vegan diet is the key to perfect health, gluten is Public Enemy Number 1, butter is bad for you…no wait….it’s good for you…sort of. The headlines in nutrition are always sensational, and always changing, and everybody and their dog has an opinion about what constitutes a healthy diet.
While your crazy vegan aunt with her nettle tea or that creepy old dude at the gym who won’t shut up about juicing are probably just full of B.S., even dietitians and nutrition researchers seem to have somewhat conflicting ideas about which diet is the best. So let’s get to the bottom of why nutrition recommendations are totally bananas!
So, what is a healthy diet? First of all, that depends on what your goals are and what your concept of health is. Are you looking to lose weight, prevent chronic diseases, or improve your energy? Or is a “healthy” diet one that can increase longevity, lower cholesterol, decrease inflammation, or improve your digestion? Researchers measure outcomes, but the problem is trying to decide which outcomes to measure as indicators of health! If weight loss is your goal, you can eat nothing but sweet, sweet Ben and Jerry’s and lose weight, so long as you’re only eating small enough portions, but what impact will that have on your risk of heart disease? And a super healthy diet rich in broccoli, kale, onions and lentils could mean hell on earth for someone with irritable bowel syndrome. So, you see, the idea of a universally healthy diet is somewhat problematic.
The catch with nutrition research is that our diet has a long-term effect on our health, so studies should be done over many years to really achieve the most accurate results. Eating red meat every day for 30 days may not increase your risk of a heart attack after 6 weeks, but follow a steak enthusiast for 30 years, and you may well find out something quite different.
Nutrition research takes time. It’s really hard to convince someone to follow a specific diet for more than a couple of weeks and therefore, it’s really hard to measure the long term impacts of a diet. In the past, researchers got around that by doing nutrition experiments on conscientious war objectors and aboriginal children in Canadian residential schools. The health and dignity of thousands of people were destroyed in the name of nutrition research and this legacy in nutrition science should not be forgotten. Now that nutrition researchers are no longer horrendous villains, they’re stuck using animal subjects or relying on willing volunteers not to cheat while following a specific diet.
Animal studies are often done in rodents and last I checked, I’m not a rodent. Rodents have a vastly different diet and metabolism from humans. So, while animal research can be a good jumping off point, we can’t draw too many conclusions based on animal research. Often, promising study findings in mice simply fail to live up to their promise when the same studies are replicated in humans.
And when scientists manage to study real humans, nutrition research is more often done in healthy young, white men. There are a few reasons for that. To start, young adults, especially college students are more likely to need a few extra bucks and hence are more willing to participate in studies. Another complicating factor is that women of childbearing age are harder to study because their metabolism and appetite can vary quite a bit depending on where they are in their menstrual cycle. And because of a complicated history of abuse and exploitation at the hands of researchers in the past, many people of colour may have reservations about participating in modern-day research. However, this creates a huge issue: despite what so many white men might believe, we aren’t the center of the universe, and a lot of nutrition research leaves out women, people of colour, the elderly and people with specific health conditions…so in other words, most people.
Another reason nutrition research gets weird is simply…money. Nutrition research just doesn’t get the same funding as, say, research into new cancer medications. Good nutrition isn’t a product that can be sold, so there’s very little potential payout to companies that do invest in nutrition research. And corporations and industries that do invest can pressure researchers into designing their studies in a biased way. Although outright corruption in research is pretty rare, it can happen and it can have huge impacts on dietary recommendations. Back in 2016, an article came out in the Journal of the American Medical Association exposing that fact that sugar industry paid scientists in the 1960s to downplay the link between sugar and heart disease and shift the blame to saturated fat. As a result, dietitians and doctors promoted a low-fat diet for several decades, leading to a whole bunch of fat-free, heavily processed foods that were high in sugar and therefore no healthier. And recently, Coca-Cola was caught funding scientists whose research shifted the blame away from sugary drinks and promoted the idea that obesity had more to do with a lack of exercise.
Even when nutrition research gets it all right (in other words: unbiased, representative of all ethnicities, socio-economic statuses or biological sex), there are also so many confounding variables. Age, smoking, alcohol use, sleep, stress, ethnicity, access to food, your gut microbiome, your food preferences, mental health, and various health diagnoses all impact your health. Researchers usually try to account for these variables through intelligent study designs and specific statistical analyses of their data, but you can see there’s quite the potential for confusion! An example could be the question of whether eating red meat increases your risk of developing heart disease. Perhaps researchers find data to suggest that it does. However, before we start to tell everyone to dump the steak and embrace the tofu, we need to consider a few other possibilities. Perhaps meat eaters also drink more, smoke more, or do less physical activity – all habits that have been shown to increase heart disease risk. And perhaps people who avoid red meat are more health-conscious and are doing other things that lower their heart disease risk. It’s hard to control for every possible factor in research, and often when a study is repeated, its findings can’t be reproduced! Hence, eggs are bad…no wait, good for you…ARGH!
The bottom line is everyone is different and will react differently to different foods. While coffee is generally thought of as a source of healthy antioxidants, researchers have found that, depending if you have a specific gene variant (and around half of us do), your daily coffee may increase your risk of a heart attack. And for me, that’s totally moot, because coffee gets me shaking like a chihuahua in a refrigerator. The interactions between our diet and our genes, known as nutrigenomics, is a brand new area of study that further complicates nutrition science and highlights the fact that there will never be one diet that’s ideal for everybody.
Nutrition research findings rarely make interesting headlines, and journalists often jazz things up in a way that makes them misleading. Take a headline like this: “Move over red wine: White wine is good for heart health and weight loss.” Sounds promising, right? Wrong! This article referred to a study done 15 years earlier that compared white wine and grape juice for weight loss. Participants who received white wine lost weight but so did the participants that drank a glass of grape juice daily. Why? Because all the participants received a low-calorie diet specifically designed for weight loss. True, those that drank the wine lost a bit more weight but that was compared to grape juice, not water. All this study showed was that adding a glass of white wine to a low-calorie diet won’t harm a person’s chances at weight loss. Journalists tend to gravitate toward research on trendy foods, or delicious foods or beverages like wine, chocolate, bacon, butter or coffee. On the flip side, it’s hard to find sensationalized headlines on the benefits of liver or okra, for example, because no one wants to be told to eat more liver. (Incidentally, liver really is a highly nutrient-dense food!).
So what do nutrition scientists, dietitians and doctors all agree on? Well, for starters, eat more plants – vegetables and fruit. It’s not exciting advice, but it is backed by hundreds of studies. And any dietitian with a pulse will tell you to avoid or minimize processed foods, like chips, snacks, candy bars, microwave dinners, deli meats, instant noodles and sugary drinks. These have been shown time and time again to increase our risk of chronic diseases. Beyond that, you’re probably best just eating foods that make you feel good and that you enjoy. And who knows? Tomorrow, your favourite food might just make headlines as a new superfood!