By reducing your calorie intake by 300 calories a day you may live longer. A study found that mice fed lower amounts of foods compared to mice feed their normal intake lived longer than the mice that ate more food. St. Louis University conducted a study and found that lower calorie diets decrease thyroid hormone triiodothyronine ( which slows metabolism ) and might increase lifespan. Starving or reducing your calorie iake does not necessarily mean you will live longer, but you will definitely have a higher quality of life.