Anecdotal evidence: I found that it's super easy to eat way more than you should by just having some food laying around. And I don't mean just Cheetos - "healthy" food will set you back rather quickly as well. The amount of exercise doesn't matter that much - with the calorie density of common snacks, you will out-eat your exercise really fast. I don't think I'm that bad in that sense, but until I started keeping a track of what I eat and the count the calories, nothing worked. Yes it's a hassle, but I vibe-coded an app that does image analysis and tracks your calories. Shameless plug: HeartLens on app store, https://apps.apple.com/us/app/heartlens-your-health-tracker/...