Health and Fitness

Why is nutrition information so confusing?

Photo credit: Arek Socha

We’re bombarded with nutrition information these days. Every day there seems to be a new study showing how this or that food may cause cancer…or eating lots of one special food (cabbage? kale? green tea?)  makes you lose weight…or that taking this company’s special supplement cures all ills. Even documented, peer-reviewed studies seem to contradict one another.

The fundamental principles of science involve combining many ideas and concepts, then testing, evaluating, re-evaluating and so on – over decades – to ultimately come to a final conclusion.

Interestingly, nutrition science is still in its infancy:

  • Macronutrients (fat, carbohydrates, and protein) weren’t discovered until the mid-1800’s.
  • Vitamins were discovered in the early to mid-1900’s.
  • Only in the past two decades have studies emerged on newer problems, such as what foods are healthy in a world of tasty, cheap, processed food where people move and exercise very little.

Below are nine reasons why nutrition science can be so confusing. [Note: content and graphics courtesy of Precision]

#1 – Nutrition research is still very young.

It takes time to master a science. Compared to chemistry, for example, nutrition science is still in its infancy.

#2 – Most research funding goes toward disease treatment – not preventative nutrition

Most researchers would rather work towards finding an end to an epidemic – not how to get rid of a muffin top.

#3 – Nutrition research is often funded by “interested parties”

Where the money comes from can often affect a study’s results. While this doesn’t mean researchers are “cheating,” corporate pressures can influence a study’s design so the research outcomes are more likely to show what the company wants.

#4 – Confounding variables make it difficult to prove the effects of food

Even in the best controlled trial, it’s difficult to isolate the effects of nutrition from all the other factors that affect human health. In fact, just the act of participating in a research study can change the outcome one way or another.

#5 – Most nutrition studies are observational

Observational studies rely on participants’ completing questionnaires about their lifestyles and eating habits. This approach is fraught with errors, as people tend to underreport what they eat, and overreport how much they exercise. Furthermore, observation-only studies can’t account for all variables, resulting in faulty and meaningless correlations.

#6 – Measurement tools always have limitations

For example, even with a straightforward question such as “how do calories affect weight” it’s difficult to get a concrete answer, because:

#7 – What you eat does not affect your health immediately

For example, to definitively prove whether red meat causes cancer would require a large group of human subjects to live in a metabolic chamber eating varying amounts of red meat for 30 years or more. Who wants to sign up for that?

#8 – You must never assume a particular study’s findings apply to YOU.

Even if you could seal a group of people in a metabolic chamber and study them for 30 years, the results would still not provide evidence of who else those results would apply to. Here’s why:

#9 – If doing the scientific research seems difficult – reporting on it is even harder

Remember this:

Hopefully these points help you understand that just because a study comes out stating that food X causes disease Y doesn’t mean the end of the world. Most importantly, remember that there is a vast difference between correlation and causation. Correlation means two things are observed to happen at the same time, but causation means one thing truly is the cause of the other – and is much harder to prove.

So how do you interpret nutritional information so it’s meaningful for YOU ? Talk to an independent nutritionist, registered dietician, or health/wellness coach – preferably one who’s impartial, meaning they are not selling a particular nutraceutical product/ supplement or commercial weight loss program. These professionals will give you non-biased, personalized advice to help you reach your wellness goals.

Laurie Kelly is a Precision Nutrition Certified Level 1 coach, specializing in exercise and sports-based nutrition coaching. She is also a NASM-certified Personal Trainer and Corrective Exercise Specialist, and a Road Runners Clubs of America Certified Adult Running Coach, and a Certified Professional Triathlon Coach by the International Triathlon Coaching Association. She’ll work with you one-on-one to help you live a healthy and active life and achieve your unique fitness goals. Contact her here or follow her blog at

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