You’ve already gotten some fabulous advice from @dchris and @MarkKO which would have addressed the standard “I’m a big guy, lifting weights, and want to lose some fat” problem; but then again it seems like you’re already doing a lot of things right.
One thing that has not been well-addressed yet:
This is already just about perfect for a fat-loss diet, so if this is really what you’ve been eating (not calling you a liar; merely clarifying - any booze? Anything else “hidden” besides this? The fact that you mention tracking on LoseIt leads me to believe that you’re adhering pretty well…)
…and you were still gaining weight at a fast enough rate that you felt compelled to see your doc, I’d be concerned about something else muddying the waters here, stress or a metabolic issue of some kind. It’s rare and a lot of people probably try to use that as an excuse for their shitty diet and lack of willpower, but if you’re lifting 4 days a week, eating that diet (which is nearly perfect) and gaining fat…something seems off.
Unfortunately, I wouldn’t necessarily trust a GP to deal with that for two reasons. One is that GP’s (actually, just about all doctors) have basically zero formal dietary training; the second is that their normal answer to any overweight patient is going to be “move more, eat less” since their typical overweight patient is probably eating poorly or not exercising. If you are, in fact, a unicorn who is eating perfectly, exercising 4 days per week and still gaining fat, this might be something beyond a GP’s knowledge. If you carry on with this routine for a few months and there’s no weight loss, it might be worth going back armed with some specifics (showing your diet and exercise log to illustrate how adherent you’ve been) and requesting a referral to a doc that deals in metabolic disorders.
Anyways. Give it a couple months of that diet, and maybe change up your training to be a little more intense, like Waterbury’s 10x3 recommended by RampantBadger. Keep us posted; stick around and start a training log.