Eat less frozen pizza
To start with, let me mention that I am going to leave out the culinary aspect. Frozen food is full of preservatives and sodium that isnt good for you. But, you will do a world (sic) of good by using less of your refrigerator while doing so. Take-out pizza is definitely a better option and isnt much more expensive. (More on take out below)
Drink less coffee
Coffee is generally a necessity for many; but, you should rarely need more than about 1 cup every 6 hours. Reducing caffeine will prevent various health issues, but, also save the trees by reducing demands on the paper cups.
Order less take-out chinese
Chinese food is one of my favorites. But, mostly this stuff is boxed in styrofoam containers. Styrofoam will go down as one of the worst man made environment killers. If you feel like chinese food, how about a sit down meal?
Eat less instant noodles / soups
Preservatives in these instant noodles and the plastic that its packaged in are not good for you nor for the planet. These are great in a pinch, but, a bit of planning helps your health and the planet.
Drink less artificially flavored drinks
Plastic bottles kill the planet. Artificial flavors hurt you.
Buy less bread with enriched flour
Whole grain bread beats enriched bread hands down in terms of environmental friendliness and health benefits.
Eat less hard candy
Whats inside is bad for your teeth. What covers it, is bad for the planet. Get a box of chocolates instead. It typically uses less plastic and more satisfying.
Smoke less cigarettes
Cigarettes are wrapped in paper, filled with leaves and generate pollutants. If you need the kick, switch to chewing tobacco. You will be harming yourself equally, but, at least sparing the world.
Buy less cheese slices
Generally speaking, higher the convenience, worse it is for planet. Individually packed slices are a prime example of this. They are good for you health wise, but, block cheese is equally good and way better for the planet.
Lessing Helps the Habitat