The most repeated myths do not survive the trials: a late dinner does not make you gain weight on its own (with the same calories, meal timing did not change weight), eating every 3 hours does not speed up your metabolism, skipping breakfast does not make you fat, detox diets do not have a single randomised trial behind them, cutting gluten without coeliac disease is not healthier, celery has no "negative calories" and a slow metabolism rarely explains why you are not losing weight. Eggs come with a nuance: they do not send cholesterol soaring, but they do raise it a little. Below, every myth with its study.
Nutrition is fertile ground for myths: everyone eats, almost nobody has studied physiology and selling complicated solutions makes money. The problem is that many of those rules ("no carbs after 8 pm", "fruit is better before a meal") sound reasonable and nobody tells you where they come from. Here a bare "it is proven" is not enough: every myth comes with the trial, the meta-analysis or the health authority that put it to the test, and with its limits when it has them.
Work it out here
Calorie calculator
The numbers already there are just an example: tap one, type yours and press “Calculate”.
A shortcut before we start: if a nutrition rule sounds magical or very specific ("this food burns fat", "never mix X with Y", "nothing after 8 pm"), ask for the study. It almost never exists, or it says something else.
Myths about meal timing
Myths about what "cleanses" or "disagrees with you"
Myths about burning energy and fat
The 12 myths at a glance
Each myth, what the studies found and the source
Myth
What the studies found
Source
A late dinner makes you fat
With the same calories, timing did not change weight
Fong 2017; Ruddick-Collins 2022
Carbs at night make you fat
Eating most carbs at dinner did not slow weight loss over 6 months
Sofer 2011
Eating every 3 hours speeds up metabolism
Same 24-hour expenditure with 3 or 6 meals
Bellisle 1997; Ohkawara 2013
Skipping breakfast makes you fat
Eating breakfast added about 260 kcal a day and 0.44 kg
Sievert 2019
Detox cleanses the body
No randomised trial in humans
Klein and Kiat 2015
Gluten-free is healthier
No link with heart attack in people without coeliac disease
Lebwohl 2017
Eggs send cholesterol soaring
They raise LDL a little; one a day was not linked to higher risk
Li 2020; Drouin-Chartier 2020
Fruit for dessert makes you fat
Same calories; before a meal, more filling
Flood-Obbagy and Rolls 2009
Negative calories
Digestion costs 5-15%, never more than the food provides
Westerterp 2004
Slow metabolism
Fat-free mass explains 63% of the differences
Johnstone 2005; Lichtman 1992
Crunches for belly fat
6 weeks with no change in abdominal fat
Vispute 2011
2 litres of water on top
2.0-2.5 litres is total water, food included
EFSA 2010
Renzy estimates the calories and macros on your plate from a photo, and you can correct them if something looks off. That way you see your daily total, which is what really counts.
Next time you read a new rule, ask two questions: which study backs it? And was it measured in people, with calories controlled? If there is no answer, it is probably a myth.
1Key takeaways: (1) dinner time, the number of meals and breakfast matter far less than your daily total: with the same calories, they did not change weight in the trials; (2) neither detox, nor cutting gluten without coeliac disease, nor negative-calorie or fat-burning foods have trials behind them; (3) eggs and metabolism come with a nuance: eggs raise LDL a little without one a day being linked to higher risk, and a slow metabolism exists to a small degree, but it rarely explains why you are not losing weight.
Nutritional information and health calculations in Renzy are for informational purposes only and are based on recognized scientific sources (USDA Food Database, ESPEN, WHO). Renzy is not a medical service: it is not a substitute for professional medical advice, diagnosis or treatment. Always consult your doctor, pharmacist or a registered dietitian before changing your diet, your medication or your supplements, and see a professional about any symptom.
