My SW leader said when I joined that you should never go below 5 syns a day and you should aim for anywhere between 10-15. She said the reason not to go below 5 syns, is because everyone has a plateau where they stick at the same weight for a few weeks. If you are only having, say 3 syns a day, there is nothing to take away to boost your weightloss. But if you were having, say 15 syns a day, you could drop to 10 and that would boost your weightloss. It seems to make sense!