Underweight and LCHF?

[LucySW]

If you are MODY or LADA chances are your not going to gain weight no matter what or how much you eat. If that is the case you will need insulin to gain. Sudden severe weight loss is an indication you may be one of those.

Yup. Low carb will minimise the damage for the moment, but more importantly, @catapillar is absolutely right. Losing weight sounds as if your body is breaking down muscle tissue because of uncontrolled high BG. Once that starts, you are at risk of DKA. You must either speed up the appointment, or test, or both. The SD Codefree is the cheapest meter and strips, get it on Amazon, and it's okay. But also, your ketones *must* be tested. You are at risk here.

It defeats me why GPs don't recognise the signs of LADA and the risk of acidosis. Thin, high BG even with carb restriction followed by weight loss = oncoming Type 1 (of whatever sub-kind) and urgent need for insulin.

Good luck - be assertive. You'll probably be fine, but you are at risk.