system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: does the body really have a ‘starvation mode’ that kicks in if you eat too little and stops you losing weight?

I hear this from time to time. If you cut your calorie intake too much your body with assume food is scarce and initiate its ‘starvation mode’ which will prevent you losing weight so quickly. Is that actually true or is it a story told to stop people following unhealthy diet regimes?  
  
And, if it is true, how can the body do this? If the body can suddenly run on fewer calories then why doesn’t it do that all the time? I guess it must have to stop burning calories on certain activities?
gpt
You'd have to miss many meals for this to start, it's a common misconception that dieting causes it or missing a meal, it's called starvation mode because you have to be suffering from starvation. Several days of no food...