How on earth have I gained weight this week

[ridingsixwhitehorses]

So in pregnancy I had gestational diabetes. Followed a low gi diet for last ten weeks of it and lost loads of weight. Was 110kg when baby went in, 106kg when baby came out. Ate like a pig for first six months and ended up 109kg.
So started low gi again a week ago. Am allowing myself carbs once a day instead of every meal. So either a sandwich at lunchtime or pasta or rice or potatoes with dinner or cereal or toast for breakfast, but only one of these. Thought it was working well for me. Feel more regulated, less hungry.
Yet today after a week I was 109.2kg. Now I know 0.2kg is very small amount but can't believe a week of far fewer carbs than usual can make me put weight on not lose it.
Thoughts please?

[Blondie1984]

How has your digestive system been since you started your low GI regime again?
Could you be a little constipated?
Have you had a lot of salty foods over the past few days that might mean your are holding on to water?

Try not to feel despondent - it might just take your body a little while to respond

[BatFacedGrrl]

Keep a food diary and be honest with yourself about portion sizes

[Dellarobia]

Is your period due? I always weigh more just before mine starts - presumably due to water retention.