My 83 year old Ma has lost her appetite. Are there any references out there for cooking or making foods for a picky eater?

Elderly people lose their sense of smell and taste. Everything tastes like cardboard. The last thing to go is the taste of sweet things, so you may have luck getting her to drink Ensure milkshakes to get the needed calories. Get some protein in her either via a supplement or another food.

Would she nibble small bites instead of eating meals? Like a 1/2 cup of frozen grapes or a coffee yogurt (or freeze yogurt into a popsicle) or cheese and crackers or nuts? Or dates stuffed with cream cheese and walnuts? Have you tried Atkins bars (chocolate pretzel is a good place to start … just sayin’) since they have a decent amount of protein? Costco has a jarred chopped olive “salad” (like muffuletta) that gives quinoa, rice, tuna fish, potato salad a punch of flavor.
By the way, these suggestions only make sense if she’s not eating because food isn’t appealing - and not if the body stops wanting food when the dying process has begun.

Appetites are weird in the elderly. My mom told me that she was never really hungry. When I asked her what she wanted to eat, she said it didn’t matter to her. She said that she only ate because she knew that she had to.

My mom was extremely thin. When she died in hospice she was nothing but skin and bones. She did like her ice cream so that was always available for her to have.

Some people aren’t all that interested in food as they age. My mom was never a big eater. She sort of grazed. I don’t like a lot of food on my plate. I don’t even use a dinner plate anymore. I use a lunch size plate for my meals. Maybe you can try smaller servings so it doesn’t look like an enormous amount of food.