I'm not a nutrition expert by any stretch, but this year I saw dramatic results by switching my diet for health reasons.  No beetus and I am not overweight, but I was at the very top end of the normal weight range for my height, and within three months I dropped 20lbs and am now solidly mid range or even a bit lower.

My secret?  

No secret.  I did what most folks have agreed for years is good - eat a balanced diet consisting of healthy fruit and vegetables, lean protein, and whole grains, while minimizing or even eliminating red meat and packaged foods, especially those high in sodium, saturated fats, and/or added sugars.  And use healthy oils when cooking.  Also, make working out a regular thing - 150 minutes a week of your heart in a workout zone.  Walking is not going to cut it.

I was not trying to lose weight, but I did.  About 1-2 lbs a week, without ever feeling like I was denying myself calories.  I've started drinking protein shakes to level off.

The other trick is that it is not "a diet."  It's "my diet."  It's not a temporary thing to achieve some weight goal.  It's embracing better nutrition...and I have finally gotten to the point where I look at the things I used to crave with a bit of disgust.  My nly regret is that I did not do this decades ago.