Myth #1 (eggs and cholesterol). The evidence supports the narrow claim that egg response is not universal, while also showing eggs do raise cholesterol on average. The Nordic Nutrition Recommendations scoping review, drawing on 38 systematic reviews and meta-analyses, states that current evidence from systematic reviews of randomized clinical trials indicates that higher egg intake may increase serum total cholesterol concentration and the ratio of low-density lipoprotein to high-density lipoprotein cholesterol, but with substantial heterogeneity in the response . The same review notes that recent evidence from observational studies does not provide strong support for a detrimental role of moderate egg consumption of up to one egg per day on the risk of CVD, especially in European studies . On individual variation, a commentary in the American Journal of Clinical Nutrition states that approximately one-third of the population has an elevated response and these individuals are known as hyperresponders, and that genetically determined sensitivity of serum cholesterol response to dietary cholesterol intake can be an important contributor . A controlled feeding study found that compared to 0 eggs, hyper-responders had significant increases in plasma total, LDL and HDL cholesterol with no changes in the LDL/HDL ratio following intake of 3 eggs/day . The AHA position is that in healthy individuals, consumption of an egg a day is acceptable in heart-healthy dietary patterns , and that a recommendation that gives a specific dietary cholesterol target within the context of food-based advice is challenging for clinicians and consumers to implement, hence guidance focused on dietary patterns is more likely to improve diet quality and to promote cardiovascular health . A 2025 umbrella review concluded that evidence regarding egg consumption has critically low strength and no sufficient quality of evidence is available to discourage egg consumption .

Myth #2 (carbohydrates and fat gain). Head to head trial evidence does not support carbohydrate as uniquely fattening. In DIETFITS, 609 adults aged 18 to 50 without diabetes with BMI between 28 and 40 were randomized to a healthy low-fat or healthy low-carbohydrate diet , and the trial found no significant difference in weight change between a healthy low-fat diet and a healthy low-carbohydrate diet, and neither genotype pattern nor baseline insulin secretion was associated with the dietary effects . Under tightly controlled feeding conditions, a meta-analysis of 32 controlled feeding studies with isocaloric substitution of carbohydrate for fat found that both energy expenditure and fat loss were greater with lower fat diets , which is the opposite of the carbohydrate-is-fattening hypothesis. The same paper notes that long-term weight loss diet studies targeting different macronutrients demonstrate similar mean body weight trajectories corresponding to a similar exponential decay of diet adherence . Separately, the controlled inpatient ultra-processed food trial found that weight changes were highly correlated with energy intake , supporting the primacy of overall intake over macronutrient identity. It is worth noting that carbohydrate restriction does produce weight loss in trials, but a review of 110 RCTs shows most were not isocaloric: approximately 30% of the trials had isocaloric intervention and control arms, 60 trials administered calorie restriction in both arms, 6 implemented calorie restriction only in the carbohydrate-restricted arm, and 13 only in the high carbohydrate arm , meaning most low-carb weight loss findings are confounded with calorie reduction.

Myth #3 (eating after 7 PM). This is the weakest of the three debunks. The word "always" is defensible, but the implication that timing is metabolically neutral is contradicted by a rigorous controlled trial. Vujović et al. conducted a randomized, controlled, crossover trial to determine the effects of late versus early eating while rigorously controlling for nutrient intake, physical activity, sleep, and light exposure, and found that late eating increased hunger and altered appetite-regulating hormones . Summarizing the same trial, a 2025 review reports that late eating significantly increased hunger and disrupted appetite-regulating hormones, notably raising the ghrelin-to-leptin ratio, and also reduced waketime energy expenditure and core body temperature, suggesting a lower metabolic rate, while transcriptomic analysis of adipose tissue revealed that late eating altered key metabolic pathways toward decreased lipolysis and increased adipogenesis . Observationally, epidemiological evidence examining the impact of late meal timing patterns is beginning to suggest that eating at night increases the risk of weight gain over time . However, the trial evidence is inconsistent. A meta-analysis reported weak evidence of a positive association between evening eating and BMI in 4 observational studies, with a mean difference of −0.39 kg/m2 (95% CI −0.80 to 0.01), however no evidence of association was shown in the meta-analysis of 5 clinical trials (mean difference −0.89 kg/m2, 95% CI −2.52 to 0.75) . A 2024 systematic review notes that prior work has been limited by follow-up durations typically under 12 weeks, limiting long-term efficacy conclusions since short-term benefits are often not sustained in the long term , with subsequent trials in diverse populations with longer follow-up showing mixed beneficial effects on weight loss and metabolic health .