Maybe look at how much you put in your plate. I know I struggle with that as I like tasty food. I found that using a smaller plate for me it helps. Also you could try filling half of your plate with salad( be careful with dressings as those have tons of calories), then you put on the other half a portion of food.
I was told by my gym trainer that squash is not good or any sugar free drinks. I taught it was fine but he said no. I trusted him.
Found also that substituting my bread with whole bread and put before hand one slice only, it helps me make it enough for me.
Also whole breakfast is good, fills you up and keeps intestine moving.
I'm telling you this as I am a person who struggles with weight and hope my tips can make a tiny bit of difference.
I also try to avoid at all the sweet or crispy snacks. I generally don't buy them either for my children. A fruit and water fills me when I'm hungry. Or I like carrots quite a bit.
Also to say I alway gain in third trimester quite a bit and I always lose it after birth( being well overweight, to not say the other "o" word). Most of my gain is water retention thou, I can see it in my tights a lot.
Also keep an eye for preeclampsia as sudden weight gain can be a symptom( I had it once).
I stick to this rules and during pregnancy I don't gain excessively.
I hope it helps.