400 calories seems somewhat high for just an hour of disc golf... are you subtracting out your BMR calories for that hour or do the 400 calories include them? If it includes them I could see it, but then that would make that number a bit (unintentionally I'm sure) misleading... What did you use to calculate the calories?
I've been playing for about 4 1/2 months now and have lost a total of 35lbs so far by combining the exercise of 1-4 rounds of disc golf (average 2 rounds/day), 30 minutes of putting practice (2x 15-minute sessions) and 30-60 minutes of field work per day along with better portion control of my meals and cutting out late-night snacks. I still eat pizza, burgers, ice cream, etc. just not as much at each meal.
I started trying to lose weight about a month before I got into DG, knew I was in bad shape so I didn't even weigh myself to start (estimate 245lbs), but after a month of 4-hour intermittent fasting and tight calorie control with Loseit I was at 230lbs. I weighed in at 196lbs. this week, hoping to lose another 15-20 but I'll probably have to get serious about counting calories again if I want to lose that much more.
Disc golf is the only exercise I've been doing this summer, so from a purely anecdotal standpoint I would whole-heartedly recommend it as a (fun) exercise component of a weight loss program!