'diet' simply means the food a person habitually eats, good or bad --i.e., we either maintain a good/healthy diet or one that isn't; however, in either case it's still a 'diet', like it or not.
i'm back to trying to maintain a healthy diet 'cause i gained far too much weight by not eating good food. years ago i set a 12-month goal and reached it but then slipped into my old unhealthy eating habits and am now paying the price for it as i, once again, set a 12-month weight loss goal (lose 100lbs @ 8.34lbs per month or better). it's a reasonable attainable goal plus it'll give me time to alter my bad habits and hopefully establish good healthy eating.
For starters, I know I can lose 0.50lbs per day if i drop from a 2000-calorie daily intake to 1500 calories, plus exercise sufficiently on a daily basis so that I burn at least 5000 calories per day at least 4 to 6 days a week throughout the year.
In order to drop to 1500 calories per day (vs 2000-2200) means eating smaller portions and watching the nutrient values like a hawk (cholesterol; fat; carbs; protein; sodium; sugar; fiber, etc) and drinking water like a fiend (80floz/day @ 10floz/drink).
I now use these values to guide me as i stick to my 1500/5000 healthy diet regime: sodium, 2200mg; sugar, 100g; total fat, 60g; carbs, 250g; protein, 60g; cholesterol, 200mg; fiber, 50g+).
What also helps me maintain this new regime is that I go to bed earlier (before midnight to quit munching) and sleep at least 6-8 hours per night.
Does this work? --it works for me, thus far, and I've lost 23lbs in 28 days (0.82lbs/per day average).
My big change, besides portion control and remembering that I now eat to live and not like before when I lived to eat, I don't eat 1000-calorie combo meals anywhere nor gulp down 20floz fountain drinks and gobble the fries or onion rings...
If I can do it, so can you, if you want. Good luck.