People are really bad at estimating portion sizes - https://academic.oup.com/ajcn/article-abstract/35/4/727/4812565 https://academic.oup.com/ajcn/article-abstra

People are really bad at estimating portion sizes - https://academic.oup.com/ajcn/article-abstract/35/4/727/4812565 https://academic.oup.com/ajcn/article-abstract/35/4/727/4812... Calories in food vary depending on how it is prepared - https://dash.harvard.edu/bitstream/handle/1/5283945/Carmody_Wrangham_JHE.pdf?sequence=2&origin=publication_detail https://dash.harvard.edu/bitstream/handle/1/5283945/Carmody_... Calories reported on food labels are often incorrect, because we digest some foods poorly and (because food companies are allowed to use multiple methods and report whichever result suits them best) - http://www2.centralcatholichs.com/copied%20articles%20to%20review/physiology/calorie%20science%20SA%20sep%2013.pdf http://www2.centralcatholichs.com/copied%20articles%20to%20r... Individual calorie absorption varies between people depending on gut biome - https://www.researchgate.net/profile/Steven_Heymsfield/publication/51818090_Individual_differences_in_apparent_energy_digestibility_are_larger_than_generally_recognized/links/0c96053065a203c368000000/Individual-differences-in-apparent-energy-digestibility-are-larger-than-generally-recognized.pdf https://www.researchgate.net/profile/Steven_Heymsfield/publi... > Also, if it's inaccurate, what's the alternative? Depends on what you're doing with it. For dieting, counting calories is probably better than not counting calories [citation needed]. For a non-preregistered non-blinded experiment testing an intervention with small effect sizes on a measure where people are known to be bad at self-reporting, well, you're already screwed. There are more direct methods of measurement (eg https://www.ncbi.nlm.nih.gov/books/NBK233774/ https://www.ncbi.nlm.nih.gov/books/NBK233774/) but they are costly.