Thanks Im 66 and did pretty much the same back and forth. Im on my second try with carnivore but more determined because my back prevents me from living a normal life. I know when i lose weight the pain goes with it.
One thing I learned was to not weigh everyday while on any weight loss diet. The time to weigh is weekly. After you get to the size you want to be, If you gain some then nip it in the bud. It's alot easier to lose 1-2 pounds than to have to lose 25-30 or more.
Yes good food cost a little more than the processes carbs but you will eat less. Going out with friends is not bad , we order meat or eggs with no potatoes or toast. The waiter looks amazed when we say no sides . My wife and myself have adjusted pretty well to this lifestyle change.
There is a good video out by a carnivore RU-vidr who interviewed 3 butchers to find cost saving ideas. I find I spend way less eating carnivore because I'm not buying all the other junk I fall prey to.