I had this too and ketones where a big problem, my midwife told me to eat small amounts and often to stabilise them. Has anyone explained what ketones are and what causes them? I struggled to understand how to control them as knowone explained what they are and what causes them but my husband found a helpful website, if I can find it I will post the link.
Best advice I can give is avoid anything that states low fat or fat free as these tend to be full of hidden sugars. Cut out sugar all together (use sweetener in cuppas, switch to diet fizzy drinks and squashes without added sugar) orange juice is a big no,, it's nothing but sugar. Seeded bread is best, for me basmati rice was better than brown rice. Eggs where a good choice to. Bulk up on veg. Other than that it's portion control really.
It does get harder to control the more the pregnancy develops but don't stress, there's light at the end of the tunnel. I lost 11kg when pregnant was induced at 40 weeks, he was 8lb 5oz, also very long. he's a happy 6 month old now.
Good luck with the rest of your pregnancy