I'd be looking at the composition of your diet, not the calories per se. You said you saw a diet doctor, was that doc impressive? Because it seems to me he should have been talking to you about fat content, carbs, the kind of carbs, the kind of fats, in other words, a whole lot about what kind of nutrition you're getting. Calories alone don't explain much.
I would definitely chase this down; 28 pounds (while fighting it) is a lot of gain in only what, four years? It's not like you're 50 or 60, when doctors do sort of shrug and say maybe it's nature's way, etc. You're not drawing a picture of that being the reason at all.
I would re-check the thyroid measurements, but also would bend every effort to find a really good dietician with a natural bent, who can tell you the difference between white rice and other more esoteric grains and why that matters, and how much of one category of food and another category you should be eating, and like that. People sometimes say "I'm eating x calories a day" assuming people know that they mean in a balanced and natural diet, but often they really aren't thinking of anything besides the calorie count. If I were to eat 1400 calories a day but get 500 of it from candy bars, my total calorie count would look fine for losing, but the sugar would put a kibosh on that pretty fast and in no time I would have a tummy, too. Has your diet changed in the last 4 years, even if just by adding one thing that you don't think is significant? (Sometimes, getting into regularly drinking a particular soft drink, sport drink or even sweet tea, is enough to up your weight gain.)
Anyway, I think you sound too young to give it up as your metabolism slowing with age. See if you can find a good doc. Ask at the local health-food store, they should know some dietary advisors.
I agree with having a recheck on the thyroid; it's one of the main controllers of metabolism and can really slow it down. Make sure when they test, they are doing the right tests. They need to be testing Free T4 and Free T3, not just TSH, which many doctors feel is the gold standard for diagnosing a thyroid problem. It would also be a good idea to have thyroid antibodies tested to determine whether or not you could have Hashimoto's, which is an autoimmune thyroid condition. One can have Hashimoto's and and of its symptoms/effects before actual thyroid hormones go out of range.
There are other hormones that can affect weight, as well. Cortisol, which is a stress hormone is one and is noted to add weight around the waist. Nutritional deficiencies can also have an effect.
Although many of us do gain weight as we age, I've read numerous articles stating that age isn't the sole reason this happens. The reason it happens as we age is because our behaviors change as we age - we exercise less/differently, we eat more/differently, etc. There are many people who age and don't gain weight.
I agree that it's difficult to get a really accurate adrenal test due to constantly changing levels caused by unlimited variables of daily life, as well as elevated cortisol in the case of those with anxiety. However, simple tests will accomplish that for our purposes.
On the other hand, it's known that when the thyroid isn't working properly, the adrenals will kick in and try to take up the slack by over-producing cortisol.
"Because it originates from the amygdyla (sic) in the primitive brain when it is issued in response to stress, it's been a difficult thing to get a handle on, as the primitive brain is very difficult to understand in it's interaction with the later evolution of the cerebrum." It isn't necessary to get that technical. The purpose of the suggested 24 hr saliva test isn't to try to get overly scientific and try to figure out a person's brain function, etc; brain function would be for a neurologist to determine.
Although brain function could be a factor that would take much more sophisticated testing than I can possibly suggest. For our purposes here, we're dealing with the relationship between thyroid and cortisol, with the understanding that there could be, but usually isn't something deeper and it would take a neurologist or psychiatrist, which none of us is, to determine brain function.
I absolutely agree with the use of herbal adaptogens to help control cortisol levels. First, one needs to have an idea what might be happening.
Here is an article I found fascinating, it's a good take on the new awareness that "counting calories" is often ineffective and why. It's a long article, but maybe you will appreciate the frustrations described. I think the findings described in the article are really important.
I'm going to ask Emily tomorrow to delete the link to the first article, it's not nearly as useful as the second one. For one thing, it keeps talking about calories as though they are a useful measure, and it mentions eating a low-fat diet as a good thing, which is by now a debunked approach. I had both articles in a row in my bookmarks, and posted the first thinking it was the second.
The article I do recommend, and the one I found compelling, was the second one. Link: