As others have noted, age and weight loss can seem like oil and water. They don't really mix that well. I'm in maintenance, but it's a constant challenge. Because I'm 75 I have to keep my carbs quite low. Also, I keep my blood ketone levels high for therapeutic reasons. If I stay around 2.0mmol/L there is no joint inflammation. This means no aches and pains. Sometimes I get pain, but that usually means I need a chiropractic adjustment.