As women age, weight creeps up too, with the average women gaining about one pound per year in their 40s and 50s, resulting in an added 10 to 15 pounds. The drop in estrogen levels during this time of perimenopause (the years leading up to menopause) contributes to weight gain and can change the way you distribute fat. You may gain weight in your belly more readily than you did in younger years.
Cortisone as an oral drug is another common culprit (e.g. Prednisolone). Cortisone often causes weight gain in the long run, especially at higher doses (e.g. more than 5 mg Prednisolone per day). Unfortunately, cortisone is often an essential medication for those who are prescribed it, but the dose should be adjusted frequently so you don’t take more than you need. Asthma inhalers and other local cortisone treatments, like creams or nose sprays, hardly affect weight.
On top of exercise, it’s nutrition. I believe they go hand in hand. In the beginning, improving nutrition was just as hard as improving fitness, except for sometimes now I think nutrition is more challenging. Exercising was just 1 - 1.5 hours a day of busting your butt, but nutrition was the remaining 22 hours, so there were way more opportunities to fall short or not eat as well as I could. However, because I think it is important to be optimistic, I will say that there were 22 hours a day to nourish my body with good and healthy foods. It just took me a long time to figure out the best way to do that (and just to clarify, I'm still figuring it out.)
Everyone is different. How quickly you burn calories when you are not physically active can be very different from other people based on your specific genes, biology, and past. While scientists know that there are 3,500 calories in one pound, simply eating 500 fewer calories every day for a week (or 3,500 fewer calories in a week) does not always end in losing exactly one pound.