Exercise and healthy eating can often help a person feel happier. Exercise allows more oxygen to reach the brain and releases endorphins, which help improve one's mood. A balanced and nutritious diet can also contribute to overall well-being, which in turn promotes happiness. A person who eats a healthy diet will likely have more energy to pursue activities that he or she enjoys.
Health is a very important aspect of happiness. You can't be happy and fulfilled if your basic needs are not met, and health is the most basic need of humans. That should be your first priority if you are looking to be happier. One obstacle, however, is that women are often taught to equate their body weight with health. This can lead them to focus more on being skinny than on being healthy. In reality, you can be skinny and healthy, or you can be overweight and healthy.
Women or men for that matter do not need to be healthy to be happy. As a matter of fact, healthy is in the eye of the beholder. A woman does not need to be fit and eat rabbit food to be happy, she could be overweight and eat junk food and still be happy. As far as finding a mate to share their life with, people like different body types, there is no specific body type that attracts people. It varies a lot.
Healthier people, on average, are going to be happier. There is really little to debate on this question. The best evidence for that is the recent reduction in life expectancy in America. The causes that are leading to the uptick are suicide, drug overdoses and other causes of death that can be reduced by healthier living.