I asked 8 researchers why the science of nutrition is so messy. Here’s what they said.

Unraveling the complexities of nutrition science can be a daunting task. Eight researchers shed light on why this field is so intricate, offering their unique perspectives and insights. Prepare to delve into the fascinating world of nutrition science and its inherent messiness.

There was a time, in the distant past, when studying nutrition was a relatively simple science

Many of the troubling diseases of the day were due to some sort of deficiency in the diet

• By the 20th century, medicine had mostly fixed scurvy and goiter and other diseases of deficiency
• In developed countries, these scourges are no longer an issue for most people

It’s not practical to run randomized trials for most big nutrition questions

It’s too difficult to randomly assign different diets to different groups of people and have them stick with those diets for enough time to find clues about whether certain foods caused certain diseases.

• Conversely, it is possible to conduct rigorous randomized control trials for very short-term questions.

Conflict of Interest is a huge problem in nutrition research

Right now, nutrition science is horribly underfunded by government – leaving lots of space for food companies and industry groups to sponsor research.

• This means, quite simply, that food and beverage makers pay for many nutrition studies – with sometimes dubious results.

Instead, nutrition researchers have to rely on observational studies which are rife with uncertainty

These studies run for years and track very large numbers of people who are already eating a certain way, periodically checking in to see who develops heart disease or cancer.

• Because these studies aren’t controlled like experiments, they’re a lot less precise and noisy.

Even with all those faults, nutrition science isn’t futile

Researchers have used all these imperfect tools to learn some important things over the years

• Without nutritional research, we would not know that folate deficiency among pregnant women causes birth defects, trans fat is bad for heart disease, and drinking too much soda increases risk of diabetes and fatty liver disease
• You should always consider all the available research on a question, not just single studies
• Different studies in different settings with different methodologies that come to similar results on the same question give a reasonably good indication that there’s a link between a particular diet and a certain health outcome
• Paying attention to the source of funding behind the research is key
• On questions of how to eat, none of the researchers talked about seeking out specific foods or cutting others

Many nutrition studies rely on (wildly imprecise) food surveys

A lot of nutrition research today rests on just that kind of information: people’s self-reporting from memory of what they ate.

• When researchers examined these “memory-based dietary assessment methods,” for a paper in the Mayo Clinic Proceedings, they found that this data was “fundamentally and fatally flawed.”
• This may be because people lie about what they eat, offering answers that are more socially acceptable.

More complications: People and food are diverse

Different bodies have really different responses to the same food

• Even getting people to better report on every little thing they put into their bodies can’t completely address variation
• There’s also the issue of food replacement
• When you chose to eat something, you’re usually eating less of something else
• A hamburger at a fast-food restaurant will have different fat and salt content compared with one made at home

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