We are not separated from nature; our physical body is as much a part of nature as anything else. One who tunes himself with the nature reaps maximum benefits and enjoys optimum health. Our bodies by nature are a distinct combination of the three doshas, which means no two bodies are the same. There is always dominance of one or two doshas, and in rare cases, there is a balance between all three.
The first major step is to recognize this nature, see where collection is happening and then remove the causative factor/s. Starving oneself is absolutely redundant, because that again is not nature, attachment to objects and fellow beings is also not nature and has to be done away with. Only taking what is required is the key whether its material things or emotions. At the emotional level, letting go of your attachments and taking more and more responsibility, not just of your immediate family and friends but the society and Creation results in sweeping away negative thoughts and purifying the being. Herbs have maximum effect on people who follow this model.
In a kapha type of person, when negative and selfish thoughts start collecting the immediate result is collection of excess fat, because kapha is heavy in nature, the heavier the thoughts one collects, the heavier one becomes. Then slowly this imbalance starts manifesting as disease. No matter how hard one tries to achieve physical change by applying physical means, the effort is going to go to waste. One must understand that it is something else which controls the physical; one has to reach there to be capable of bringing a change. People, who are of vata nature, get more affected by imbalances like arthritis, asthma, indigestion and hypertension affecting the heart. All these are effects of obesity of thoughts, actions, and the body. Pitta type of people encounter stomach ulcers, hyperacidity, colitis, gastritis, etc. So herbs and asanas or exercises are not so effective for these people and they have the tendency to get exposed to life threatening diseases.
All three types people need to bring themselves to the prescribed state and then the effects of herbs would be miraculous. Whenever there is excess, there is collection and we should know that we are violating the law of nature.