Yes, you can eat mangoes. Mangoes are not worse for weight loss.
You can safely eat them even on a diet, provided to eat them in small portions and don’t go bingeing on them. A 100-gm serving of ripe mango pulp has a mere 60 calories! Do not eat it along with lunch or dinner but eat it before breakfast or as mid day meal in morning or evening. Avoid in night time. For diabetic especially, take in a small quantity only.