Food and diet ond outings

Does it mean that you should not eat out at all when you are on diet. Generally when we go on a family outings during weekends we tend to give a different taste to our taste buds. But what about the dieting times.
What are the food items that you can eat out when you are on diet. Here I am talking about Indian foods.
The below list of foods help in reducing your weight and also helps in reducing the tummy.
1. Cucumber
2. Sundal
3. Green leaf vegetables -avarai, keerai, beans, etc.
4. Water melon
5. Apples

But can we eat these things when we go for an outing.??