Losing weight while breastfeeding

Syvilla • Above all love each other deeply, for love covers over a multitude of sins. 1 Peter 4:8

So my son is 9 months and I’m trying to lose weight but all the weight loss apps don’t account for breastfeeding. Me and my husband went vegetarian recently to try and help but I’m just wondering does anyone know of any good apps that give a good baseline for caloric intake restriction while breastfeeding?