OP's writing doesn't sound British, at least to this Brit. The last sentence, "What will be a good way to stay in shape", reads as non-native, even, due to the non-idiomatic use of "will" (compare "What would be" or "What is" here). Dropping articles (the, a, an) is a feature of the English of people whose first language is Russian or another Slavic language - just guessing.

The post you are replying to drops an article on "trainer" near the end. Could also just be shorthand/hurried/casual writing, though - like this sentence. That poster otherwise uses "the gym".

On topic: +1 to getting a personal trainer if you can afford the money and time.

I assumed it was an American thing. Gym is a noun.