Muscle Atrophy

Pretty much what the others said. When you are on a long term calorie deficit, you WILL lose muscle, along with fat. You can minimize how much muscle you lose by lifting HEAVY weights. Heavy means you can do 8 to 12 repetitions, maximum, before resting. If you can do more than 12, the weight is too light. You'll still lose muscle, but yhe percenrage will be less.

You can build strength at the same time you are losing muscle. Strength and muscle mass are not the same thing.

The only way to add muscle mass is eating more calories than you burn. But, obviously, you add more fat as well, and gain weight.

Bodybuilders go through these well established cycles, called cutting and bulking. They bulk -- eat excess calories, lift heavy, and gain muscle and fat. Then they cut -- eat fewer calories, lose fat, but a little muscle. Over time, they end up with a bunch more muscle, and by cutting right before a competition, they look really well defined.

So, lift heavy if you are able. But keep the calories as low as you are can. Use the honeymoon period to get rid of the excess fat. You can worry about adding new muscle when you reach goal.

I complained about similar pain about the same time around my knees (which I suffered from for years) and new pain in my back. My surgeon advised that some of it is because I was much more active due to the exercise requirements and so there was some soreness... but more so, she said it was because of the weight loss we carry ourselves differently (like pregnancy in reverse) and it strains the joints and muscles as they get used to the new you. I can report happily that the majority of pain is now gone and only when I push myself or stand for many hours (like when I'm painting plein air) or doing heavy work in the garden. Arthritic knees and ankles and back/neck really are literally a pain, but movement does help in the long run.

I'm 3 months post op and have have aching and painful joints, knees and hips the past 3 weeks but idk the reason. When I lay down at night they ache like a tooth ache .