There are three main body types that have been identified, but due to genetic variation, it is usually impossible to put anyone firmly into one of the categories. Instead, people are usually a mix of all three, but with a predominance of one particular type. The different types are as follows:
Left to Right: Mesomorph, Ecto-Mesomorph, Endomorph, Ectomorph.
Image graciously donated by Cody Frost
Endomorph: Often unpleasantly labelled the 'soft body', endomorphs put on muscle easily and retain it for a long time, but are cursed with a very conservative metabolism which makes fat retention common. Endomorphs can usually play to their strengths by being much stronger than other counterpart body types, but losing the fat around the abdomen can be very difficult indeed. Most world-class powerlifters are endomorphs and, as a practical example, Burt from the Carpe-Diem webcomic is probably iconic of this body type.
Ectomorph: With smaller muscle bulk and little body fat, ectomorphs are usually the polar opposite of endomorphs - they have great difficulty gaining and maintaining muscle bulk, but are nearly always very vascular, with very visible muscles. Ectomorphs are unusual in bodybuilding competitions due to their lanky and bony nature, but not unknown. This body type is usually found on basketball players, and other sports where speed, but not necessarily strength, is needed.
Mesomorph: With the best of both worlds, mesomorphs are a mix of the other two body types. They gain muscle relatively easily, retain it well, and have a fast metabolism. This means that they can also eat large amounts of food and still remain thin. Most championship bodybuilders are mesomorphs and, as a practical example, Kevin from the Carpe-Diem webcomic is probably an iconic mesomorph.
Training by Body Type
Endomorph: Despite being loathed by many endomorphs starting on the road to greater fitness, cardiovascular training is a must, and needs to be carried out on a regular basis. As the greatest nemesis of an endomorphic body type is a slow metabolism, it will pay great dividends to space out aerobic exercise into smaller sections each day, rather than in one great big lump on a single day each week. This should also extend to weight training - i.e. circuit training, supersets, etc, are highly recommended in the medium rep range, and although it is very tempting for the endomorph to lift heavier weights to impress others, the aim is to keep metabolism up instead of showing off. A repetition range of 10-15 is usually best. A heart-rate monitor is also ideal, as it will allow you to keep within your target heart rate range and maximize fat burning.
Ectomorph: Ectomorphs have a very hard time putting on muscle, so the main aim of training is to cause maximal stimulation of muscle fibers. For this reason, ectomorphs should train with heavy weights and aim for low rep sets, with longer rests between sets (i.e. 2-3 mins). Since metabolism is always high, cardiovascular training is not essential and should be carried out at leisure for short periods of time only.
Mesomorphs: As the 'middle man' between the other two body types, training for mesomorphs is fairly predictable. The ideal type of training is often said to involve heavy weights performed with interspersed super sets, compound sets, & giant sets to promote maximum intensity and, therefore, muscle growth. Cardiovascular exercise is still a necessity, but not as much as in endomorphs - 20-30 mins 2-3 times a week should be more than sufficient.
Diet by Body Type
Endomorph: Troubled by a slow metabolism, endomorphs have to pay far more attention to their diet than the other body types. To enhance metabolism and keep energy levels constant it is generally recommended to eat smaller yet more frequent snacks rather than 3 bigger meals a day. Saturated dietary fat needs to be controlled, but with careful attention paid to carbohydrates, which are often packed into 'low fat' alternatives. A thermogenic supplement may be of help for losing the weight initially, but they all come with their own side effects and are no alternative for a carefully controlled diet in the first place.
Ectomorphs: Ectomorphs are victims of their own metabolism, and, for this reason, find it hard to ingest enough calories to maintain growth. For this reason, they need to eat lots of starchy carbohydrates and protein at every meal, with moderate amounts of fat. They also need to eat much more frequently than other people - 6 to 8 times a day is a must to keep nutrients firmly in the body. This is not an excuse to 'pig out' of course - meals should not be junk, but at the same time pasta and red meat is definitely your friend! Supplements such as multivitamins and protein are highly recommended.
Mesomorphs: Traditional 'balanced' diets are usually written for the mesomorph in mind, meaning that their diet should consist of lots of good quality protein, moderate amounts of complex carbohydrates, and suitable levels of good quality (i.e. unsaturated) fats. Just like the endomorph, it is generally recommended that the 'main-meals' system is abolished and instead split up into several smaller yet more regular meals. There is, however, no need to go quite as overboard with this as the ectomorphs.
Well, that's it! Of course, this article is no substitute for more detailed guides to proper nutrition and exercise, but it should help you identify your body type and put you on the right track. Striving for personal physical perfection is not an easy task, but with hard work and a little knowledge, it can become a whole lot easier! Best of luck!
Edited by Zak