It seems like there’s a new study with some sort of dietary health recommendation every week, and often the latest results contradict what we’ve heard before. Just in the past couple of weeks, a study came out claiming that the low-carb diets so many of us have been encouraged to follow may actually be shortening our lives. Another group of researchers announced that their findings suggest moderate alcohol consumption is not the way to go, that there is in fact no safe level of drinking. The examples go on and on.
It’s confusing. And all the conflicting results can actually undermine public trust in science, as a whole.
John Ioannidis is the C. F. Rehnborg Professor in Disease Prevention, Professor of Medicine, and of Health Research and Policy at Stanford University, and he believes it’s time for a change.
Ioannidis recently wrote an op-ed in the Journal of the American Medical Association about the challenges of improving nutrition research. He believes that the odds are not great in terms of getting reliable answers, first, because the questions that need to be answered are extremely complex.
“It's very difficult to disentangle all the biases that exist and therefore most of the research results that we get are not very reliable,” Ioannidis said. “On top of that, you have an extra layer of dissemination in public media that probably make even more of the stories than they really are.”
From there, stories get spread widely and false information can be passed along. Some of those deceptive headlines, the ones that claim that eating a certain food every day will make you live longer, are especially misleading. That’s because, according to Ioannidis, almost every nutrient is connected either positively or negatively to some other nutrient.
“So even if you assume that there are many of these nutrients in foods and that they may have some causal relationship to things like death. By analyzing large amounts of data, you're doomed to find significant associations with practically every nutrient and every food group,” Ioannidis said.
Ioannidis would also like the media and researches to focus back on the basic rule that if we eat more, we will become obese if we have the same level of energy expenditure. He warns that the idea that you can eat whatever you’d like if the foods are “quality” foods, can be harmful.
“The more we eat, the more fat we become. And you know there's probably differences across people based on their metabolic profile and their genetics, but this is pretty much a rule, and focusing on telling people that you can eat more food if it's good quality food. I think this is misleading."
Ioannidis believes that there are things that can be done to avoid these issues, one is to look at the tools that are being used in research. He recommends that researchers report all results from each data set for all the possible combinations and associations so that they can compare different nutrients and food groups.
Another would be to try to perform more randomized trials. That means that instead of just observing what people do, or even asking them what they did and what they ate, try two randomized approaches. With that, you can find out what Ioannidis calls “intention to eat.”
"We need a moratorium on big claims about nutrition and how exactly to eat in order to live better and longer,” Ioannidis said.
He left us with some personal nutrition tips, void of any claims to about what specifically to eat.
“Don't eat too much. Try to be moderate. And avoid deficiencies.”