How can I help my nutrition. What are the most nutritious cheap items at burgerking, mcd, and jackbox?

Water, fruit. A bottle of water and a serving or two of fresh fruit without any sauce, sugar, or anything else. That's it.
Burger king. 10 nuggets for $1.49 at burger king is really inexpensive nutrition. At McDonalds that would cost about $2.50 Now try to have a drink without sugar.
Nutrition Facts. Nutrition facts are often available from many chain restaurants. BK: https://www.bk.com/pdfs/nutrition.pdf, McD: http://nutrition.mcdonalds.com/getnutrition/nutritionfacts.pdf, JB: http://assets.jackinthebox.com/pdf_attachment_settings/106/value/Nutritional_Facts.pdf Set a goal for calories (2000 for example), consume less than 50 grams of sugars/day. Drink water instead of anything else.