Carb levels

Hi Zoe, My question is: is there a minimum level of carbs we should be eating? A few of us, when reducing our carb levels to doing some days of zero carb and alternating days of 20 to 50g carbs, have experienced bad sugar cravings and ended up bingeing. Is this because we went too low with our carb levels or a sign that we are addicted to sugar? I seem to be fine when I do one day of zero carbs followed by one day of 50g carbs, but if I drop it to 20g carbs one day and zero the next, after a day or two I am consumed by cravings. I just seem to 'need' my day of a few oats, a bit of milk, fruit, chocolate etc. I am wondering whether it is psychological or physical and wondered if you know which it might be.