Answer:
Not always.  It is true that any type of diet which results in an increase in fruits and vegetables and a decrease in fat is likely to improve health. With some individuals, however, eliminating meats, eggs, and dairy products without increasing consumption of fruits, vegetables, grains, and legumes may simple make a poor diet worse. [...]

Answer:
Yes. Vegetarians tend to smoke less, consume less alcohol, and exercise more. The vegetarian type diet, however, is still protective even when lifestyle risk factors are excluded. In other words smoking, excessive alcohol consumption, and a sedentary lifestyle are risk factors for both vegetarians and omnivores, but vegetarians may suffer the consequences of bad habits [...]

Answer:
The lower risk of coronary artery disease and hypertension may be due to lower intake of saturated fat and cholesterol, plus greater intake of potassium, antioxidant nutrients, certain vitamins, plant sterols, and other phytochemicals. Lower risk of several forms of cancer may also be related to the protective effects of increased consumption of phytochemicals, antioxidants, [...]

Answer:
A qualified yes. Epidemiologic and case control studies in vegetarian groups show lower all-cause morbidity and mortality. In prospective studies, carefully selected vegetarian diets usually result in several positive health outcomes when compared to traditional eating habits. the benefits include decreased risk of coronary artery disease and hypertension, lower body mass index, fewer deaths from [...]

Answer:
The typical American diet is high in protein and sugars and fairly high in saturated fat, omega-6 fatty acids, total fat, and total calories. Meat consumption is relatively high. Fruit and vegetable intake is less than optimal, at approximately 2-3 servings daily. The diet is low in fiber and relatively low in omega-3 fatty acids. [...]

Answer:
A lot of variants and sub variants of the vegetarian diet. The two classic variants are

Lacto-ovo-vegetarian- simply avoid meat, poultry and fish. They eat no meat but will consume animal products such as milk, cheese and eggs.
Strict vegetarian or Vegan diet- excludes all animal products, limiting the diet to only those foods produced in [...]