We're looking at Earth science observing our planet. Also space science looking at the ozone in the atmosphere around our Earth. Also looking at life science. And on a human level using ourselves as test subjects.
If you continually diet you are putting your body in a quasi-famine situation. It slows your metabolism down and breaks the thermostat. Diets don't work. They don't help you understand why you're eating more than your body wanted in the first place.