I was morbidly obese (300+ lbs) most of my adult life. This was a huge insecurity that held my dating, sex life and self-confidence back in my 20's. Then I lost 120 lbs. I've been ~180 6'0" for the past few years.

For guys asking "should I date now, or lose weight first". Do both! Cut your calories and exercise now. But also talk to lots of women now too.

Experience is important. If you postpone dating until you lose weight, you'll run into a problem. You may have a good body, but you'll still have the same social skills as that 300 lb guy who plays video games all day and never goes outside. You may get opportunities, but you'll lack the experience to take those opportunities.

So, even if a fat guy gets rejected 3x as much as a fit guy, he should still try. Because he's getting experience and learning from it. Also, getting 1/3 as many dates is still a lot more than zero.

What surprised me is that even halfway along my weight loss I was noticing a difference. When I went from 300 to 240, halfway, I was super confident in myself even at that weight and I had a few girls hitting on me. At the time, I couldn't believe it. I thought I had to be <200 for anyone to ever like me.

Even if you're fat, you should still get a nice haircut, be well groomed, dress well. Don't be afraid to spend some money to look better. If you use dating apps, take professional quality photos. But if apps aren't working out, try real life too.

As for how I lost weight (and kept it off for years), I did calories in/calories out. Calorie deficit. Count every single calorie you eat, including beverages, condiments, etc. I ate basically anything as long as it fit my calories and protein requirements. The important part is having a sustainable lifestyle - not a fad diet. Eat foods you enjoy (in moderation). Do exercises you enjoy. If you don't like what you're doing, you won't stick to it.