We got a 5yo rescue beagle just before lockdown last year. We all adore her- she's affectionate, calm, silly, absolutely devoted to us all and the most loving of animals I have ever met. A total joy. (Took some work but she knows we are here too now.)
She is also overweight (came to us like this and I have weighed her this weekend and I am failing her, she hovers around about the same weight).
Like with lots of beagles she has no recall. And so I can't let her off the lead. But it also means she doesn't get the opportunity to run, and as much as we both need the exercise I don't have 3 hours a day to walk the same calories off. There is a secure exercise field about 10 miles away so we have been there a few times but she's not interested in running games- she doesn't find fetch or anything like that exciting so I cant chuck a ball/stick about there or in the garden for her. She just looks at it and then wanders off.
So my focus needs to turn to food- she is a greedy little thing
but has two small meals a day and 1 dental stick plus 2 slices of non-naice ham (she's a stubborn mule too and it's the only way I can get her to move out of her basket to go out for a wee past 8.30 PM when she likes to retire) Although will grab anything that she can because she's a beagle. Last week it was an entire home made lasagne for 8 that was defrosting on the kitchen table 
This is a long waffle (basically me just loving how idiosyncratic my lovely pooch is!) But the crux of it is- I need a low calorie but filling food I guess- there are lots out there, are these ok for them? Is there something else I can do? (Other than cutting back massively on the treats, I MUST be giving her more than I realise)
TL:DR my dog is overweight. More exercise might not be the best route. Please recommend a diet food for her.