Why Science-Based Diets Get It Wrong
Every day headlines announce:
- a new government nutrition guideline, or
- the latest science-based diet, or
- a promising clinical trial.
Sometimes it feels like there is way too much advice to sort though. Especially when even experts disagree with each other.
Even worse, when you try following the latest nutrition/diet advice, 99% of the time it doesn’t work or gets overturned by new research.
Have you ever wondered why this happens?
The reason(s) might surprise you.
The main reason is very simple.
But there are a host of subtle reasons as well.
Garbage In = Garbage Out
Dietary guidance and nutrition advice based on faulty human memory.
These data, which underpin most of the advice from the Dietary Guidelines, ask consumers to remember what and how much they ate in the last 24 hours.
- Unfortunately, well over half of consumers do not report eating enough to stay alive.
If the data that go into diet and nutrition advice are flawed, then the correlations between dietary choices, health, and disease may be wrong.
To put it more bluntly:
Garbage In = Garbage Out
This means that much of the current nutrition advice and science may be wrong.
Seeing Is Believing
If well-intentioned science using bad data sounds depressing, here is a short humorous video of the truth that will make you laugh:
What About Scientific Research?
As I’ve observed previously, the health and fitness industry is broken due to:
- Bias towards short-term sales of information products:
- They get your money upfront, and you get a diet book or exercise DVD.
- Bias against long-term transformation and results:
- When the diet or exercise program stops working, the blame implicitly falls on you.
As a result, we tend to trust more authoritative sources such as Web-MD or clinical studies.
But nutrition and fitness science is a trial-and-error process that yields clues and not a one-time event that gives final answers.
- The good news is that the the scientific process is inherently self-correcting,
- (although this sometimes it may take years or decades).
- The bad news is, although the scientific methodology is a fantastic tool,
- nevertheless it suffers from inherent flaws.
Flaws In Research Methodologies
Every year I read upwards of 500 research abstracts, summaries, and reports and more than 75% of the time I see one or more of these flaws:
- Many nutrition or supplement studies are performed on people with clinical deficiencies.
- If you are not deficient you will not see any benefit (i.e. more is not better).
- Many studies on are on unhealthy or untrained subjects.
- The thing is, almost everything works on unhealthy or untrained subjects, due in part to the “placebo effect”.
- Generally things that work for overweight people don’t work for athletes, and vice versa
- Chronic versus Acute are completely different conditions:
- What works for chronic condition (diabetes) may not work for an acute condition (DOMS)
- Metformin stimulates fat-loss (via AMPK) but inhibits building muscle (via MTOR).
- Many studies are short-term and underpowered.
- Almost anything different works….that is, shows some novel effect for the first 6 weeks.
- Many observed “effects” do not rise to the level of long-term statistical significance.
- Poor study design:
- Many studies lack simple “washout periods” and “cross-overs” and make misleading inter-subject/group comparisons.
- ‘p-hacking’ whereby data is mathematically reversed-engineered to produce a novel result.
- Fun-fact: 96% of science publications will not accept “null result” research papers, i.e. that disprove something old.
- What works in one population or genotype may not work in another.
- Most research is done on young male trained college athletes….their results may not apply to you.
- Many research studies use pharmaceutical grade nutrients or supplements.
- Store-bought Supplements are often adulterated:
- Natural or herbal supplements are sometimes just ground up stems or rice powder.
- Bodybuilding supplements are sometimes spiked with pharmaceuticals (legal or otherwise)
- Doctors and Instagrammers are not trained experts in nutrition, fitness, or wellness.
- Your average TV MD hawking their latest diet book appeals to medical authority, but in fact has little or no formal training in nutrition.
- Examples: Wheat Belly, The China Diet, Bulletproof, 4-Hour Body, Dr Oz, David Avocado Wolfe, …..
- Even 2-time Nobel prize winner Linus Pauling created the Vitamin Myth.
- Sponsored research
- While not all sponsored research is bad, a lot of it contains design biases that favor the sponsoring organization.
- I have seen zero null-result sponsored studies. Coincidence? I think not :)
- Qualitative conclusions unsupported by quantitative data.
- Watch for studies where participants subjectively “feel” improvements not objectively measure or supported by the actual study data.
- Mechanistic or reductionist interpretations:
- ‘X causes Y’ thinking treats the body like maintaining a car.
- In really, the human body is a intricate and complex “system of systems” tending towards homeostasis (dynamic equilibrium).
- It’s really really hard to prosthetically improve on Mother Nature.
- Medicine is create at fixing pathological disease, but far less effective at promoting quality of life or wellness.
- A lot of nutrition advice and many supplements are just derivatives or reductions of what you could get from eating adequate fruits and vegetables.
Looking to the future, I see the rise of fitness apps and wearables such as the Apple iWatch and MyFitnessPal improving data accuracy. They are a much lower cost solution than ‘metabolic wards’ where trial participants are medically supervised and supplied with measured food and highly supervised exercise.
What You Can Do
With so much questionable nutrition science and fitness advice in the news, what can you do?
- If you don’t already, subscribe to my monthly newsletter where I analyze the latest health and fitness news, gadgets, and trends (example).
2. If ARE a subscriber, simply email me your question to me at email@example.com
3. Upgrade your Social Media to include reputable analysis of health & fitness news. I personally use the following (feel free to pick your own):
Originally published at The Healthy Executive.