Absolutely. I agree with that.
I am on a diet right now to lose some weight I gained during the covid-19 lockdown (around 3 kilos) and my doctor told me that, first, eating properly and healthy food is a must; and then, practise some exercise will help for sure. I don't know if it's a 75% vs. 25%, but for sure diet is the major component for losing weight.
“Yes, you can lose weight with diet alone, but exercise is an important component. Without it, only a portion of your weight loss is from fat — you're also stripping away muscle and bone density. … “As a rule of thumb, weight loss is generally 75 percent diet and 25 percent exercise