Acclimating to LC

I have been living a LC lifestyle since 2001. At that time, I quickly
and easily lost just over 25 pounds reaching my lowest weight in 30
years. Now, ten years later, I'm almost back to my original starting
weight. While I'm not as rigid about LC as when I was losing weight, I
am pretty consistent. No bread, no potatoes, no desserts, no sugar
drinks, no candy, no fruit, no milk, no....

Sure, as the body ages, it becomes more difficult to lose weight. My
physical activity is about the same or slightly higher than it was in
2001. My food portions are slightly less. My blood work and medical
tests show that I'm in great shape. (I have minor hyperthyroidism, but
it is fully under control and regulated.)

It's clear that one or more of the follow problems is causing my weight
gain:

1. Eating too many calories
2. Actually getting less exercise than I think
3. Eating too many hidden carbs
4. Body changes from the aging process

My question is whether the body acclimates itself to low carb eating
such that I am unable to reduce my carb intake any further and lose
weight. As I sit here typing this post, I've removed all of the fun
stuff (carbs) from my diet, but I'm gaining weight.