Meat doesn't generally cause people to gain weight and usually avoiding it doesn't work out well as a healthy way to lose weight...
I'm not against vegetarianism, and in complete honesty I don't especially like the taste of meat. But the foods that tend to be the worst for weight management are empty carbohydrates, including sugars, potatoes, corn, and low fiber breads. I think you'd have more luck by reducing your intake of those substances than you will just by cutting meats...... Dropping red meats and increasing your fish and poultry is a good choice, too - but for reasons other than weight loss (fish contains beneficial fats and oils that your body uses to rebuild its self, too much red meat in the diet can increase risks for colon cancer, etc).
You're going to have much better success with weight management if you get rid of white breads, fast foods, candies and cookies, and potatoes and pasta than you ever will by avoiding animal products. The human race survived primarily on vegetables and meats long before they ever learned to agriculturally supplement their diets with grain and sugar.
I've lost about 40lbs in the last year from cutting my carbohydrate intake down to only dairy and vegetable sources on a daily basis, and limiting my breads to whole grains and fruits to berries a few times per week. I don't have potatoes/sweets/pastas/fried food/etc more than once every month or so. My cholesterol, blood sugar, and iron levels have all greatly improved and are now at normal levels.
