Circuit training with weights is good for losing fat while maintaining joint health as you're not placing emphasis on 1 muscle group the way bodybuilding would. If you're dieting to lose fat and build muscle then you'd want to aim for 1 gram of protein per pound you weigh or maybe 20 grams less than your weight. That is the recommended amount for either muscle development or strength training.

Here are collections that might help. Good luck and best wishes!
Healthy Nutrition https://grokker.com/cooking/collection/healthy-nutrition/603ad327b356ab7d31b48ff0
Barre https://grokker.com/fitness/collection/barre/605edc48c1a5914c3303952c
Billy Blanks, Jr., Jess & Lexi, Keaira LaShae, PopSugar, Tracey Mallett, More https://grokker.com/fitness/collection/billy-blanks-jr-jess-and-lexi-keaira-lashae/6009cdd43fa6704a3439c188
Cardio Kickboxing https://grokker.com/yoga/collection/cardio-kickboxing/60ce41d64cb7214269a7e826
CrossFit, Barbells, Mudruns, Football https://grokker.com/fitness/collection/crossfit-barbells-mud-runs-football-plus-warm-ups/6009d3963fa6704a3439d0ef
Pilates https://grokker.com/fitness/collection/pilates/605edf53c1a5914c330396b3
Strength & Cardio https://grokker.com/fitness/collection/strength-and-cardio/603fff68b356ab7d31b99cbc

Strength & HIIT https://grokker.com/fitness/collection/strength-and-hiit/603f8f46b356ab7d31b8ef00
Ellen Barrett, Jane Fonda, Denise Austin https://grokker.com/fitness/collection/ellen-barrett-jane-fonda-denise-austin/603ad1c4b356ab7d31b48e73
Sarah Kusch & Kelly Lee https://grokker.com/fitness/collection/sarah-kusch-and-kelly-lee/603ac20eb356ab7d31b47e78
Fitness with Agnieszka of Fitappy https://grokker.com/fitness/collection/fitness-with-agnieszka-of-fitappy/6009f0913fa6704a343a26c1
Fitness with Cassey Ho of Blogilates & Pop Pilates https://grokker.com/fitness/collection/fitness-with-cassey-ho-of-blogilates-and-pop/6006436d2321c749b61b0f3d
Fitness with Pace & Go https://grokker.com/fitness/collection/fitness-with-pace-and-go/6075d41c40ba6b32542cc076
Fitness with Team BeFit and Scott Herman https://grokker.com/fitness/collection/fitness-with-team-befit-and-scott-herman/60138cad644d5e152de2a513
Fitness with Team Tone It Up https://grokker.com/yoga/collection/fitness-with-team-tone-it-up/60061d752321c749b61acf19