Separating nutrition science from marketing claims

Clients arrive with nutrition opinions already formed. The course description for The Science of Nutrition uses a concrete comparison: the share of consumers who actively seek information about nutrition and healthful eating rose from 19 percent in 2000 to 46 percent in 2011. Much of what they find is advertising. A fitness professional does not have to be a dietitian to avoid passing that advertising on. The job is to slow down and ask what the claim is actually based on.

A useful claim names a person, a food or a nutrient, an amount, and an outcome. “Protein builds muscle” is a slogan. “In this study, trained adults who lifted and ate a stated amount of protein gained more lean mass than the group that lifted and ate less” is a finding, and it still has limits. Those limits are the part worth learning. Who was studied? Was it ten people or several hundred? Did they train, or were they at rest? How long did it last? Who paid for it? A six-week trial in young men does not tell you what a postmenopausal client should eat.

Mechanism is not the same as a result

Marketing likes a mechanism because it sounds scientific. A compound “supports mitochondria” or “balances hormones.” A mechanism explains how something could work. It does not show that people who take it get the result in the advertisement. When you read a claim, separate the story of the pathway from the measured outcome: body weight, strength, a lab value, a symptom. If the only evidence is the pathway, you do not yet have a reason to recommend the product.

The same split applies to single studies and to guidelines. One paper can be wrong, underpowered, or later reversed. Dietary guidelines exist because many lines of evidence were reviewed together. The course points professionals toward guidance from the Academy of Nutrition and Dietetics for that reason. You can explain a guideline without pretending you wrote it, and you can say when a new paper has not changed the guideline.

What to say in the session

You can be useful without pretending to prescribe. Ask what the client read, what they changed, and what they hope will happen. Repeat back the claim in plain words. Then say what you know, what you do not know, and who should answer the rest. A trainer can teach a client to look for the amount, the population, and the outcome. A trainer should send a client to a registered dietitian when the question is a medical diet, an eating disorder, or a supplement stack.

Three questions cover most headlines you will be shown on a phone:

• What was measured, and in whom?
• How large was the change, and compared with what?
• Is anyone selling the thing the headline praises?

If the answer to the third question is yes, and the answers to the first two are missing, you have a promotion, not a finding. Say that calmly. Clients trust a coach who will say “I don’t know, and here is how we could find out” more than a coach who has a product for every article.

The Science of Nutrition spends its early lessons on the biology underneath these conversations: what digestion and absorption actually are, and how energy nutrients differ. That background is what makes the three questions possible. The guides on this site start the same way. Calories and the energy nutrients is the next page. Credit for the full course is separate and is described on the continuing education page.

These ideas are taught in more detail in The Science of Nutrition, a 5-hour continuing-education course for fitness professionals. To enroll, call customer service.