Diet Plan

I’m new to the whole diet thing and was wondering if this was a low calorie diet plan or if it’s too high?

Breakfast:

- 1 piece of whole grain toast

- 6 cheery tomatos

Lunch:

- 1 Tin Of Tuna

Dinner:

- 1 piece of whole grain toast

- 1/2 an Avocado

Snack:

- 1 Apricot