Maybe you are trying too many things. If you keep switching diets and are doing too much exercise, your body is trying to balance itself. it might also be caused by lack of sleep or too much stress. Do moderate exercise and start eating a little bit cleaner and the pounds will come off. If you still don't notice a difference, talk to your doctor. You might have a thyroid problem or some other medical issue.
If you’re only getting a minimal amount of sleep each night, that leaves more time for you to snack and make otherwise unhealthy decisions that could affect your weight loss. Although it will vary from person to person on how much sleep you actually need to be most effective (and therefore make progress toward your weight loss goals), the ideal number is typically 7 or 8 hours, says Dr. Cheskin.
Popularized by the documentary Forks Over Knives, the Ornish diet is a low-fat, plant-based diet plan based on whole grains, vegetables, fruits, and legumes. It's based on a lacto-ovo style of vegetarianism, allowing only egg whites and nonfat dairy products. It's packed with vitamins, fiber, and lots of filling plants to keep you satiated. Some studies have shown it can reverse heart disease and have beneficial effects on other chronic health conditions. (BTW, there is a difference between a vegan diet and a plant-based diet.)