Originally Answered: I need a diet plan of 1200 calories.?
It's easy to stay under 1200 calories if you stay away from meat and dairy products. These types of foods are very high in fat, with low nutrient to calorie ratios. I have been a vegetarian for 2 years, and have lost 10 pounds without trying (and I was in the low healthy weight range before I changed). That said, if you do decide to eat meat, eat lean meats and fish.
I usually eat something like this:
Breakfast: Sprouted wheat bagel (TONS of protein) with 1 tbsp tofutti "better than cream cheese" (300 cals)
OR 1 cup whole foods brand roasted wheat cereal with 1 cup light vanilla soy milk (silk) (190 cals)
I've also recently discovered these amazing frozen waffles from whole foods (pomegranplus), and there are only 180 calories in 2 of them, they've got a fair amount of protein, and they're incredibly filling.
I usually have breakfast with green tea or tazo awake tea, but if you like coffee, try it without adding cream and sugar (maybe skim milk/soy milk)
Lunch: Whole wheat bread with tofutti cream cheese and pomegranate superfruit spread (230 cals)
OR Whole wheat tortilla wrap with some hummus and lots of spinach and veggies (carrots, tomatoes, roasted peppers, roasted eggplant, etc.) you could also add some lean meat to this
I have lunch early, so I usually have this just with water, but a good snack to have with this would be fruit/veggies
Snack: a big bowl of spinach salad with some non-fat raspberry or non-fat ginger dressing or potato chips! (they are SO easy to make, you add no oil, and they take about 4 minutes in the microwave: http://blog.fatfreevegan.com/archive/2008_08_01_archive.html) (under 50 cals)
I usually have this either with fruit, or I make a bagel pizza with half a sprouted wheat bagel, tomato sauce, and a tiny tiny bit of fresh mozzarella cheese (around 150-180 cals total)
Soup is amazing. You can make a huge pot of it and freeze part of it, and as long as it's not cream-based, it has very few calories. One night this week, I made about 4 cups of miso soup from scratch (it takes less than 10 minutes of active cooking) and ate it all for dinner. It sounds like I pigged out, but in reality, it was only around 200 calories (2.5 servings of tofu = 175 cals + 3 tbsp miso paste = 40 cals + seaweed = 10 calories)
There are some delicious, healthy soup recipes on this website: http://blog.fatfreevegan.com/2005/12/soups.html
For snacks, try to stay away from packaged stuff. That said, if you don't have much time, packaged foods can be easy snacks. Ryvita crackers are really healthy and good with goat cheese or hummus or cream cheese with fresh strawberries or even just plain. Fruit also makes a great snack. Here's a delicious, warm, quick, healthy fruit recipe: http://blog.fatfreevegan.com/2010/01/microwave-baked-apples-two-ways.html
And here's a delicious recipe for cookies with only 78 calories each! http://blog.fatfreevegan.com/2010/02/banana-maple-oatmeal-cookies.html
And all this food doesn't even add up to 1200 calories, so you can increase portion sizes or eat more meals throughout the day (it's healthiest to have 6 small meals per day).
I know this might be too general, but following these guidelines have helped me remain thin. I only drink water, seltzer, and tea. Once in a while I'll have watered down juice (because if you don't drink sugary drinks very often, they taste extremely sweet). A cup of juice has at least 140 calories, and that's the all natural, no sugar added kind. So you can drink a cup of juice, or eat almost a cup of pasta.
Oh, and my favorite website also has a section of "ridiculously easy" foods to cook: http://blog.fatfreevegan.com/2010/02/banana-maple-oatmeal-cookies.html
Sorry if this got really rambly! Food is kind of an obsession for me...
Good luck with your weight loss! I think it's great that you're so dedicated!