Research
A Diet Can Work And Still Be Wrong About Why
From the FASTER syllabus: this article is taught in full in Results-Based Nutrition Coach, £750 →
In short: A client's diet result and a diet's founding story are two separate claims, and only one of them needs checking against research. Results-Based Nutrition Coach's Common Diets module teaches trainers to run every diet through the same separation: the Palaeolithic diet does show some real controlled improvements in glucose tolerance, blood pressure and lipid profiles (Lindeberg et al., 2007), but the course's own research on diet success points at adherence and total energy balance, not ancestral genetics, as the actual reason (Gardner et al., 2018). A trainer can back the result and question the story without repeating an unproven claim to a client.
The short version
A client mentions a friend who lost weight on the Palaeolithic diet, cutting out grains and dairy to "eat like our ancestors did," and it's easy to hear that as one claim when it splits into two: the friend did lose weight, and the story about ancient genetics is a separate thing, standing or falling on its own. FASTER's Results-Based Nutrition Coach course teaches its Common Diets module around exactly that separation, run across seventeen different approaches so it becomes a habit rather than a one-off argument.
Key Takeaways
- A diet's result and a diet's founding story are two separate claims. A real result doesn't prove the story, and a weak story doesn't disprove the result.
- The Palaeolithic diet does show real short-term improvements in controlled trials, but the course's own research on diet success generally points at adherence and energy balance, not ancestral genetics, as the likely reason.
- Once a course is passed, PT Manager is where a coach's actual reasoning about a client's plan gets kept against their record.
The two claims hiding in one sentence
"My friend lost two stone on paleo" sounds like a single fact, and it splits into two the moment it's checked properly. Claim one: did the friend lose weight? Very possibly yes, and there's no reason to argue with a result someone can see in the mirror. Claim two: was it because human bodies are still wired for a diet from before farming existed? That's a much bigger claim, standing on its own evidence, and it can be separate from whether claim one is true.
What the research says
The course takes the Palaeolithic diet seriously. Controlled trials show improvements in glucose tolerance, blood pressure and lipid profiles on Palaeolithic-style eating, even over short periods. What those same trials don't establish is the ancestral-genetics story behind them, the claim that modern bodies are mismatched to farming-era food and that's why the diet works. The course's own research on diet success in general points somewhere plainer: adherence and total energy balance predict results better than which pattern a client follows. A plan built around avoiding grains can work for the same reason a plan built around anything else does. It gets followed.
Nobody has to win this argument
Nobody needs to tell a client their friend is wrong, because the friend isn't wrong about the result. The skill the course builds is holding two things steady at once: the outcome is real and worth taking seriously, and the explanation offered for it is a separate question that gets checked on its own. That's an easier conversation to have well than picking a side in a diet argument, and it's the one a client respects, because their own result never gets questioned.
The same separation, run seventeen times
The Common Diets module runs the same test on sixteen other approaches. Whole-food and vegan patterns, intermittent fasting, the ketogenic diet, low-calorie approaches, intuitive eating and more each get asked the same two questions: what result does this produce, and does the story behind it hold up on its own. Paleo is just the clearest worked example of a skill that applies to whichever diet a client mentions next.
What to do next
Results-Based Nutrition Coach, £750, teaches how food is used, works through every diet on its own merits, and builds the coaching skill that gets a client to change. Once a course is passed, PT Manager opens real clients for good, and a coach's own reasoning about a plan gets saved against their record there rather than re-argued from scratch each time it comes up.
The FASTER Journal shares the next teaching point first. Sign up at /newsletter and it arrives the moment it's ready.
You just read one answer. The course is all of them.
Results-Based Nutrition Coach, £750 — taught by the people who wrote it, with free return access for life. The price is on the page, payment plans at checkout, no sales calls.
Also worth a look: PT Manager, free the day a course is passed.
See what the course covers →Frequently asked
Does this mean the Palaeolithic diet doesn't work?
No. The course text is clear that controlled trials do show real short-term improvements in things like glucose tolerance and blood pressure. What it doesn't show is that the reason is ancestral genetics rather than the plan simply cutting out processed food and being easy enough to stick to.
So what actually explains most diet results?
The course's own research on diet success generally points at adherence and total energy balance mattering more than which specific pattern a client follows, which is why matching the diet to the person is the bigger lever.
Does the Common Diets module cover more than the Palaeolithic diet?
Yes, seventeen approaches, from intermittent fasting to low-calorie diets to intuitive eating, each run through the same separation between the result and the story behind it.
Reading this for your own training? Every trainer on the FASTER register has been assessed by us — search by town or speciality, free.
Find a FASTER trainer →
