Most who write about diet actually dont know what they are talking about unfortunately.
Weight Watchers has changed. It has gone keto.
If anything, older folks need more protein.
I know Brendan in NZ who lost 200 lbs and has kept it off living the keto life, who was invited to talk to the Secretary of ______, I forget now, of NZ to discuss keto. He hand him a ten page dissertation on keto. It is a growing, actually exploding, weight loss option.
CHeck out Dr BIkman, Dr Jason FUng, Dr William Davis, Dr noakes, Ivor Cummins, Tina N. and the list goes on.....
DietDOctors.com is one of the best websites; A group of doctors banned together to fight city hall.
( I mostly live on a food and nutrition and dieting forum, looking at the latest research, best health practices, which tests to get and why, what food is causing health problems, how the medical profession is behind the times, and the pharmaceutical impact on government agencies and doctoring, how to buy the cleanest foods..... all because I got a chicken some 8 years ago, lol)