Trouble is, you're under section due to being too ill to be safe. So not engaging with the psychiatrist fully when he's asking a completely relevant question about things that happen to people with eating disorders and, in the case of hormonal swings, are very relevant for any woman with mental illness or personality disorder, isn't helping you.
One of the things that contributed towards you being placed under section is that you weren't engaging with your female doctors, either. To say now that there is a problem because the psych is male does seem to me likely to be an excuse/deflection away from addressing the symptoms and consequences of your recent situation.
If your periods have stopped, you're at increased risk of osteoporosis. If they are heavy, you are at increased risk of anaemia, which, combined with restrictive/no eating, increases the likelihood of heavier bleeding in a vicious circle. If they are irregular and accompanied by huge swings in mood, there could be a hormonal element to your difficulties which could potentially be treated differently. You could have other things going on unconnected to your MH. But they won't have a chance of finding and acting to alleviate them if you won't respond.
You need to stabilise and improve. But putting another barrier in the way, just as you did when you said you would have Ensure drinks, but not the food, when there weren't any Ensures available, does sound more like you're trying to deflect and distract. Just as you refused and avoided following the requests and recommendations of your female doctor, just as you were saying you didn't have an ED, so shouldn't be asked or expected to have tests, just as you were saying that you weren't happy you weren't being referred to an ED unit or treated the same as your friend, this is trying to avoid and evade things you find uncomfortable.