About Body Types

Here is the info on how to train for the three different body types. If you you are somewhere in between two body types and recommendations would be a middle approach.

Endomorph:

An Endomorph's biggest concern should be the losing of fat and adopting a lifestyle that keeps it off. Strength training should be done to get a better muscle to fat ratio and therefore improve metabolism. Use moderate weights at a fast training pace (very little rest between sets and exercises). You should lower your calorie intake (but not try to starve yourself) and should eat frequent but small meals. Sugars, sweets and junk food should be eliminated from your diet. Engage daily in some activity like brisk walking, biking, etc., and try to increase the amount of time you spend each week.

Mesomorph:

A Mesomorph has a naturally fit body but to maintain it or improve it they should exercise and diet correctly for their type. Strength training can be done more often and for longer sessions then would be good for an Ectomorph, but you must still be careful not to overdo it. You should train with moderate to heavy weighs and at a moderate pace, not resting too long between sets. You will find you gain muscle quite easy (some women and even men might not want to get too bulky, but this won't happen suddenly. When you are happy with your muscle size simply train to maintain it). Stick to a good healthy diet to keep you lean and muscular, and watch for any slow creeping fat gains. Engage in and enjoy aerobic activities, sports, etc. but do not overdo.

Ectomorph:

Ectomorphs should concentrate on gaining weight in the form of good lean muscle tissue (some women that are too thin may also want to put on a little fat to look more feminine). Weight training should be done but not too often or for too long each session. Weight should be fairly heavy and workout pace slower (longer rest periods between sets). Diet should be high in calories (good quality food not junk) and you should eat more then you're used to and often. Aerobic and other activities (sports, dancing, etc.) should be kept to a minimum, at least until you are happy with your weight and looks.

History

In the 1940s, Dr. William H. Sheldon introduced the theory of Somatypes. His theory described three basic human body types: the endomorph, characterized by a preponderance of bodyfat; the mesomorph, marked by a well-developed musculature; and the ectomorph, distinguished by a lack of either much fat or muscle tissue. He did also state that most people were a mixture of these types.

Dr. William H. Sheldon (1898-1977)—A Forgotten Giant of American Psychology.

Sheldon's description of three body types has become an integral part of most literature on weight loss, fitness and bodybuilding.
The three body types are further described below.

Ectomorph:

• Fragile
• Thin
• Flat chest
• Delicate build
• Young appearance
• Tall
• Lightly muscled
• Stoop-shouldered
• Large brain
• Has trouble gaining weight
• Muscle growth takes longer

Mesomorph:

• Athletic
• Hard, muscular body
• Overly mature appearance
• Rectangular shaped (hourglass shaped for women)
• Thick skin
• Upright posture
• Gains or loses weight easily
• Grows muscle quickly

Endomorph:

• Soft body
• Flabby
• Underdeveloped muscles
• Round shaped
• Over-developed digestive system
• Trouble losing weight
• Generally gains muscle easily

Conclusion

When you know which type you are (or which mixture) and diet and exercise correctly for that type, you will make much better progress.
While some women may think that Kate Moss is the ideal, from a fitness view point she really isn't. And many women who tend to be endomorphic will save themselves much suffering by not striving to change themselves into ectomorphs, it's not going to happen. Conversly a true ectomorph who wishes to be a Sumo wrestler would also be in for a big disappointment.
Your goal should be to look as close as possible to (or stay looking like) a mesomorph. With the correct exercise and diet this can be attainable, and while you may be a bit upset that you have to work hard to look good while the true mesomorph looks that way naturally, at least you will still be fit and look good. And even the mesomorph will find as he/she gets older that some exercise and diet is needed if they want to continue to look good and be fit.