The world of nutrition is filled with advice, guidelines, and rules about what to eat and what to avoid. However, recent research is questioning the very foundation upon which many of these recommendations are built. This article explores why the data from long-running nutrition surveys might be more flawed than we thought and what this means for our understanding of healthy eating.
We’ll delve into the issues with self-reported dietary habits, the unreliability of observational studies, and the concept of ‘Vibration of Effects’ (VoE) that challenges the validity of nutrition claims. Instead of promoting a one-size-fits-all diet, we’ll introduce an alternative approach, the ‘Rule-of-Thumb’ diet, offering a set of heuristics to guide you towards a healthier and more enjoyable way of eating. Get ready to rethink everything you thought you knew about diets and nutrition!
What’s new?
The data from the world’s longest-running and largest nutrition surveys, once considered an ocean of knowledge, is now revealing a ‘Pacific-Garbage-Patch’ equivalent of junk. This discovery calls into question past diet recommendations and admonitions that science has thrown at you.
Why it matters:
Nutrition science often tries to translate correlations between dietary habits and health outcomes into a universal ‘best’ diet. This approach is futile. Scientists should instead help individuals find the best diet for themselves, even if it’s unsuitable for others. This article offers two takeaways to help you navigate the confusing world of nutrition:
- A thorough understanding of why diet recommendations derived from observational studies are fatally flawed
- An 8-item Rules-of-Thumb “diet” – an alternative for you to find the healthiest diet that you can actually enjoy
First: Are nutrition societies toast?
If nutritionists admit that the data driving their recommendations is flawed, their credibility is at risk. Two recent papers highlight the issue: people often misreport their dietary habits, invalidating studies that correlate diet with health outcomes.
As early as ten years ago, experts called for journals to stop publishing research based on inaccurate self-reported data [1]:
“the use of decidedly inaccurate instruments to accurately measure EI [energy intake] or PAEE [physical activity energy expenditure] needs to be discontinued. In this case, the adage “something is better than nothing” must be changed to “something is worse than nothing.”
The Titanic Dimension of Nutrition Science’s Credibility Problem
Two studies shed light on the issue. The first study examined the gap between self-reported and actual dietary habits among 30,000+ participants in the National Health and Nutrition Examination Survey (NHANES) from 2007 to 2018 [2]. Only a small fraction of those claiming to follow low-carb or low-fat diets actually met the criteria when queried with 24-hour recalls.
The second study [4] used a gold standard technique (doubly labeled water measurement – DLW) to objectively measure total energy expenditure (TEE) in nearly 6,500 people. This allowed researchers to compare TEE with self-reported energy intake. The results were striking:
In a nutshell: Doubly Labeled Water is like tracking the “exhaust” (CO2) from your body’s engine to see how much fuel (calories) you’re burning overall. It also gives a reasonable, but not perfect, estimate of your body fat percentage [5].
The study found that a significant portion of participants underreported their energy intake, and this was correlated with BMI: the higher the BMI, the more likely they were to underreport. Additionally, those who under-reported their intake also reported a disproportionately high protein and low fat intake. This is why researchers suggest ignoring observational studies and using tools to highlight dietary misreporting [4]:
“…highlight the true level of dietary misreporting … and … not rely so much (or at all) on self-report.”
Applying this tool revealed that over 50% of dietary reports had implausible energy intakes and therefore, likely erroneous nutrient intakes. This challenges the reliability of surveys like NHANES.
The Iceberg
The ‘Iceberg’ refers to the ‘Vibration of Effects’ (VoE). This occurs when different statistical models, used to analyze relationships between variables like nutrient intake and health outcomes, produce different conclusions. In other words, researchers can often find whatever they want in the data.
Vibration of effects
John Ioannidis demonstrated VoE using NHANES data [6], showing how controlling for different confounders (like age and sex) affects the correlation between biomarkers and survival. With multiple variables, numerous relationship models can be constructed.
Ioannidis applied 8,192 different models to 417 biomarkers collected in NHANES. The outcome? For many variables, different models produced different outcomes, with some showing that a variable could extend lifespan and others shortening it.
This means that observational datasets about nutrition and survival can support contradictory claims. It raises questions about the validity of headlines touting the benefits of ‘superfoods’.
A Lifeboat?
If nutrition scientists are uncertain about their recommendations, can celebrities offer better advice? Celebrities have endorsed numerous diet fads, from Atkins to the Alkaline Diet. However, their endorsements are often based on trends rather than scientific evidence.
Consider the tapeworm diet:
The tapeworm diet, popular in the early 1900s, involves ingesting tapeworms to consume calories. While a hoax, it highlights the absurdity of some diet trends. Even a celebrity like Khloe Kardashian once jokingly suggested wanting a tapeworm to get slim.
With both nutritionists and celebrities providing questionable advice, what should you do? The answer lies in a ‘Rule-of-Thumb’ diet.
The Rule-of-Thumb diet: A radically new approach to feeding
The most reliable conclusion from diet studies is that your diet should be the healthiest one you can actually enjoy. It should be nutrient-dense, calorie-adequate, enjoyable, and easy to implement. This is where the ‘Rule-of-Thumb’ diet comes in.
This diet avoids specific food restrictions. Because, one person’s best diet can be another person’s worst.
The 8 Rules of Thumb
Here are 8 heuristics to guide you towards the healthiest diet you can reasonably get. Don’t strive for perfection; aim for progress.
Rule #1: the one-third-two-thirds rule
Get two-thirds of your daily micronutrients from one-third of your meals.
This rule focuses on ensuring adequate micronutrient intake without constant worry. Consider the concept of the daily ‘anchor meal’.
Example: A breakfast smoothie packed with essential micronutrients allows you to worry less about the nutrient density of other meals. This works because you follow a daily routine and it’s always the same.
Rule #2: Farm-over-Factory
Choose foods closer to their farm origin than to the factory. This prioritizes whole, unprocessed foods.
Example: A steak or roasted chicken is preferable to a frankfurter sausage, which is an ultra-processed food (UPF). UPFs are often calorie-dense, nutrient-poor, and rich in additives.
Another example: Bread
Homemade bread, made with flour, yeast, water, and salt, is processed. Store-bought bread falls into the UPF category.
Factory foods and restaurant meals are designed to please your mouth, not your body, and are filled with hidden sugar, unhealthy fats, and additives that do a number on your health.
Rule #3: Fiber is a friend
For plant-based foods, the higher the fiber content, the better.
Example: A whole apple is better than apple juice. Whole-grain bread, made with the entire grain, is better than refined grain (white flour).
Rule #4: Color your plate
Include a variety of colorful plant foods on your plate to ensure a diverse intake of micronutrients and polyphenols.
Rule #5: the 3-minute let-your-brain-catch-up-with-your-mouth rule
Eat slower to allow satiety signals to kick in. Take a three-minute break halfway through your meal or before taking another serving. This helps prevent overeating.
Rule #6: Step on the scale, daily!
Daily weighing helps maintain weight by providing immediate feedback on calorie balance. Early detection of weight gain allows for timely adjustments.
Rule #7: Listen to your gut.
Pay attention to your body’s reactions to different foods. What’s healthy for one person may not be for another. Listen to your body.
Example: If you feel bloated after eating store-bought bread, consider baking your own to see how you react to the ingredients.
Rule #8: Exercise: Just do it!
Combine a healthy diet with regular exercise for optimal health. A sedentary lifestyle can negate the benefits of even a perfect diet.
What I do
All eight rules are key. Rules #1 and #8 are most important. #8 has the strongest impact on health. #1 keeps my food intake optimal even with my preferences.
I dislike vegetables and love meat. I don’t follow vegetarian, vegan, or planetary health diets. I need meat. I accept that everyone’s path to a healthy diet is unique.
Nutrition science should focus on helping individuals find a diet they enjoy, rather than creating flawed one-size-fits-all recommendations.
How about you?
What do you think about the ‘8 Rules-of-Thumb’ diet? Is there anything I should add or anything you disagree with?
Let me know in the comments section.
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Now here is the promised brief on the DLW method:
DLW
Doubly Labeled Water (DLW) is a method to measure total energy expenditure (TEE). It involves consuming water with stable isotopes of hydrogen and oxygen. The different elimination rates of these isotopes allow accurate calculation of CO2 production, which is then converted to calories burned.
DLW also estimates body composition, though not as precisely as energy expenditure.
Cited References
[1] Dhurandhar N V, Schoeller D, Brown AW, Heymsfield SB, Thomas D, Sørensen TIA, et al. Energy balance measurement: when something is not better than nothing. Int J Obes (Lond) 2015;39:1109–13. doi:10.1038/ijo.2014.199.
[2] Kowalski C, Dustin D, Ilayan A, Johnson LAK, Belury MA, Conrad Z. Are People Consuming the Diets They Say They Are? Self-Reported vs Estimated Adherence to Low-Carbohydrate and Low-Fat Diets: National Health and Nutrition Examination Survey, 2007–2018. J Acad Nutr Diet 2024;125:239–246.e1. doi:10.1016/j.jand.2024.07.006.
[3] Park Y, Dodd KW, Kipnis V, Thompson FE, Potischman N, Schoeller DA, et al. Comparison of self-reported dietary intakes from the Automated Self-Administered 24-h recall, 4-d food records, and food-frequency questionnaires against recovery biomarkers. Am J Clin Nutr 2018;107:80–93. doi:10.1093/ajcn/nqx002.
[4] Survey N, Health N, Examination N. Predictive equation derived from 6 , 497 doubly labelled water measurements enables the detection of erroneous self-reported energy intake 2025;6. doi:10.1038/s43016–024–01089–5.
[5] Westerterp KR. Doubly labelled water assessment of energy expenditure: principle, practice, and promise. Eur J Appl Physiol 2017;117:1277–85. doi:10.1007/s00421–017–3641-x.
[6] Patel CJ, Burford B, Ioannidis JPA. Assessment of vibration of effects due to model specification can demonstrate the instability of observational associations. J Clin Epidemiol 2015;68:1046–58. doi:10.1016/j.jclinepi.2015.05.029.
[7] Zarzo I, Merino-Torres JF, Trelis M, Soriano JM. The Tapeworm and Maria Callas’ Diet: A Mystery Revealed. Parasitologia 2022;2:160–6. doi:10.3390/parasitologia2030015.
[8] Ge L, Sadeghirad B, Ball GDC, Da Costa BR, Hitchcock CL, Svendrovski A, et al. Comparison of dietary macronutrient patterns of 14 popular named dietary programmes for weight and cardiovascular risk factor reduction in adults: Systematic review and network meta-analysis of randomised trials. BMJ 2020;369. doi:10.1136/bmj.m696.