Looking for help for my 63 year old Mom

I agree. She certainly is not eating enough or very healthy. Maybe the fruit and yogurt for breakfast. She definitely needs protein and fat at each meal. I know she will freak out on the fat, but if you can get her to read about it maybe that would help. Fat is critical for health and loss. I don't eat animal fats unless butter is considered animal fat. I have coconut oil, ground flax, almonds, olive oil, a little mayo. I eat boiled eggs not just whites and avocados. I am 58 and lost 35 pounds in 1.5 years. I have lost 15 pounds in 2 months since I totally changed my diet and went low carb, high fat. There is a lot of info on that approach and the more I read, the more healthy it sounds. I eat 1200-1400 calories/day and I do work out 45-60mnutes 5 days/week.

Good luck.

Actually at 63 your bmr is drastically reduced. My mother, 49, comes out to about 1250 for a 1lb a week loss, and that is with about half an hour of exercise a day. As long as she is getting a balanced diet and not hungry your grandma is probably fine at ~900. It sounds like you don't think she is eating anywhere near that though and that has less to do with her calorie goals and more to do with her desire to lose weight quickly. Entire different problem. If you can get her to eat 1000 cals a day legit, she is probably just fine. My grandma wouldn't eat much but then would have candy bars when no one was watching, she died of diabetes but was probably pretty close to the calories she needed.

Actually at 63 your bmr is drastically reduced. My mother, 49, comes out to about 1250 for a 1lb a week loss, and that is with about half an hour of exercise a day. As long as she is getting a balanced diet and not hungry your grandma is probably fine at ~900. It sounds like you don't think she is eating anywhere near that though and that has less to do with her calorie goals and more to do with her desire to lose weight quickly. Entire different problem. If you can get her to eat 1000 cals a day legit, she is probably just fine. My grandma wouldn't eat much but then would have candy bars when no one was watching, she died of diabetes but was probably pretty close to the calories she needed.

Where are you getting your information from? BMR is only reduced by loss of lean body mass... we just usually lose LBM as we age and, thus, our BMR reduces proportionately. That said, when we gain weight, our LBM increases right along with fat mass.

Another way to explain it is that age alone doesn't necessarily reduce BMR... it's just if your weight remains the same over the years, your BMR will likely reduce as you lose LBM and add fat, which is what happens as people give up regular exercise.

Your BMR does lower as you age. In addition to the less muscle mass and bone density, your hormones also shift. You can lift weights and exercise to try to maintain as much muscle mass as you can, but you can't prevent all muscle loss as you age. And unless you supplement with hormones, you can't do much about the effect those have on your BMR either.
Even the very few women who are professional weightlifters in their 60s, still experience a decrease in their BMRs from when they were in their 20s and 30s. It is just the way it is.

To the OP- the most important thing for your mom is to make sure she has sufficient protein in her diet. This, along with regular exercise, will help prevent as much muscle loss as she can. I know my mom would never eat enough protein, and her health suffered because of it. She would rather just eat crackers or other simple carbs and that wreaked havoc on her diabetes, and her hair was almost completely gone by the time she passed away last summer.
Healthy fats are important as well, for many reasons.

If she is not overly active, 1000-1200 cals a day is probably fine for her, as long as she is getting enough protein and healthy fats in. I would say a very minimum of 50 g of protein, but closer to 70 if possible.
Have her write everything down that she eats for a week, (or log it on here if she is a member) and see just how many calories she is eating and what her macros are.

How is her health other than being overweight? Does she have diabetes?

ETA- If she is working every day and is not losing weight, most likely she is eating more than you think she is. She most likely is a 'snacker' and doesn't eat much at meal times, but snacks here and there thru out the day. She also may be drinking her calories in sodas, juices, coffees, etc.