It's no secret that what you put in your mouth affects your health. New "health food" trends arise each year and subsequently go the way of the dinosaur. But our #ketoveganlowcarbpaleorawblessedalkaline diets aren't saving us. Anyone who has been paying attention attention to the state of healthcare in this and multiple other countries can see that the obesity rate is rising, which in turn has led to increases in the prevalence and incidence of preventable diseases such as hypertension, type II diabetes, and cardiovascular disease. These illnesses, as you might suspect, significantly increase the rate of morbidity and mortality. And what is the most common cause of obesity? This may not be a popular opinion, but it is caloric excess. But is simply eating too much food all that's to blame for what we term "cardiometabolic" mortality?
It is unlikely that this is the case. Although caloric excess and obesity play a significant (and most likely the largest) role in increased cardiometabolic deaths, data continues to be released that diet composition may also play a significant role. A large-scale study from the Journal of the American Medical Association of 702,308 of these deaths in 2012 with evaluation of mortality trends from 2002-2012 showed that an increased intake of what most of us would consider to be "unhealthy" foods (I use that term colloquially, as moralistic and dogmatic judgments on food are idiotic) was associated with a large portion of these deaths. Decreased intake of "healthy" foods was also involved in this association. Based on the investigators' analysis, which involved a bunch of fancy statistical testing that you all probably don't care about, 45.4% of cardiometabolic deaths in 2012 were directly associated with "suboptimal" intakes of these foods. That's right. Almost HALF of the deaths from cardiac disease, stroke, and diabetes in the US were most likely due to poor diet.
The question you're all thinking was my first one with this study too: "what foods were involved? What should I stop eating?" Well, if you know me (and know nutritional science), the answer is nothing. There is no food (provided you eat it in moderation) that is going to kill you. Except pufferfish. Don't fuck with teterodotoxin. There are some foods you might want to avoid consuming in large quantities, however, if you want to lead a long and healthy life. The foods/nutrients most associated with cardiometabolic death in this study are not shocking: excess sodium, processed meats, and sugar-sweetened beverages. Low intake of the following foods/nutrients actually increased mortality risk: nuts and seeds, seafood omega-3's, vegetables, and fruits. Consumption of whole grains, unprocessed red meats, and polyunsaturated fats did not seem to have the same impact.
I don't know about you guys, but I am not remotely surprised by these findings. Based on what I have seen in both epidemiologic data and my own clinical practice, I honestly thought the mortality percentage might even be higher. What did surprise me, however, is that the investigators supposedly controlled for energy intake during this study, meaning that it was not excess caloric intake that led to the increased mortality rate. This was performed via the "residual method," which I'd argue is questionable at best. They also claim to have used this method to control for BMI (insert rolling eyes emoji here). The foods most associated with these diseases are not only high-calorie, but hyper-palatable. Are people who consume more of those really likely to be consuming the same number of calories and have the same BMI as those consuming more fruits, vegetables, and fish? I HIGHLY DOUBT IT. In addition to this, the investigators used a 2-day recall of intake when polling participants in the study. Unless you're tracking your food intake relatively closely (which people who live healthier lifestyles are also more likely to do), this method is highly inaccurate. Essentially, the people who were likely consuming less calories, had lower BMIs, and lived healthier lifestyles had a lower risk of cardiometabolic death.
So where does this leave us? What can we learn from this study? Well, first, that confounding variables are a big deal, and we need to always look out for them. They can really skew results, and often cause (or allow) people to misapply important scientific information. Confounding variables are one of the reasons nutritional science is so difficult, and can also lead to misguided individuals creating nonsense documentaries that make physicians and scientists facepalm so hard that we get concussions. However, the information gleaned from study is helpful. It helps to confirm what we already know: that eating shitty food makes for poor health outcomes. Yes, this equation is more complicated than the Law of Thermodynamics, but HIGH-CALORIE, HYPER-PALATABLE FOODS cause problems long-term in almost everyone. You know what foods these are. People don't need a degree in nutritional biochemistry to know what foods they should focus their diets around. Do your best to avoid processed stuff and sugared drinks (most of the time), eat lots of fruits and veggies, and make sure you are including healthy fats while eating appropriately-sized portions. Lean meats appear to be a little less important, as unprocessed red meat did not seem to cause much of an issue, so we have no reason to fear it (in the proper amounts, of course). Additionally, we now have stronger evidence to reference from when making dietary recommendations as a society. Even though much of this information is relatively intuitive, to make policy changes such as food labeling, school lunch programs, and dietary assistance, we need more studies like this. This large-scale analysis may have had some methodological issues, but it certainly adds fuel to the fire for those preaching lifestyle medicine. Keep those portions controlled, eat the right stuff, and stay strong and healthy, folks!