Doc wants me to only consume 30-50 grams a fat a day

So far this has been a big help https://stanfordhealthcare.org/programs ... titis.html on what foods to avoid, but nothing on calories. If I followed their diet, I would lose weight rapidly.
Otherwise I am 32 year old who can exercise and lift weights. I would like to consume 3,000-4,000 calories if possible. I am 6'0 and 175lbs. I would like to maintain weight, it took over 4 years to get to 175lbs, I was 150lbs since high school. Only reason I got to 170 is because I avoided docs advice, not a good idea. But now I am just skinny fat.
Any advice on diet plan please?
weight training consist of squats, deadlifts, military press, barbell curls and push-ups.