It's normal to have to go to the bathroom after you eat. Putting food in your stomach causes a reflex that stimulates the colon to empty.
One thing you could do is keep a food log and see if any particular foods tend to produce the gas. Some high fiber veggies will do it (think beans), and some people lack the enzyme (lactase) needed to digest the sugar (lactose) in milk products.
If it is lactose intolerance, you will need to reduce dairy consumption or take a lactase supplement when you eat dairy. You can also find milk with the lactase in it.
Beano can help if it's due to beans and veggies.
Amazon.com: Beano Food Enzyme Dietary Supplement Tablets, 100-Count Bottles, (Pack of 2): Health & Personal Care
Some people like to use probiotics.
Probiotics & Probiotic Supplements - WebMD: Uses and Safety
If the food diary does not help you determine the cause, see your primary care doctor. S/he can determine whether you need to see a specialist or not.