Hard gainers in other words!  Long legs and arms, low body fat percentage, and small muscles. While some women wouldn't find it a problem to have some of the characteristics of this body type, men will probably see it in a different way! Unlike the mesomorph and the endomorph, the ectomorph is the person that has probably been very skinny their entire life. It's not because of a great diet or workout, it's because they are born with a super fast metabolism. This gives them the "ability" to eat pretty much whatever they want, whenever they want, and never get fat and never gain weight.

Training:
If you are an Ectomorph, you probably will benefit the most if you train with heavy weights. You will want to stimulate your muscles "deeply" in order to have the training response you want and increase your muscle mass. Exercises using free weights (barbells & dumbbells) are great at achieving this. They allow you to use full range of motion and are said to be best at mimicking natural human body movement. Performing workouts using heavy weights taxes your body and you will need to make sure you are resting and recovering fully between training sessions.  Ectomorphs usually have a faster metabolism and burn their calories rapidly so don't be too concerned about cardiovascular training for now. Unless you wish or have to do cardio for personal reasons, you should initially concentrate on gaining lean muscle mass by weight training.

Diet:
Remember that your nutrition is at least 70-75 % of your overall training results! So even if you are naturally thin you need to eat complete, frequent and healthy meals/snacks. Always supplement with daily multi vitamins and minerals. Things like amino acids, protein shakes or selected herbs provide you with an integrated approach to training and are yours to discover!

 The endomorph has the slowest metabolism of the three different body types and can therefore gain weight the quickest and easiest. Known to have a "soft look", it is harder for them to trim and tone through exercises and diet.  This is great for gaining muscle and strength, but terrible for losing and keeping off fat. It's basically the complete opposite of the ectomorph.

Training:
Endomorphs would benefit from circuit training, super-sets, compound sets or other similar routines that focus on enhancing the metabolism. Heavy wight lifting that limit total repetitions is not recommended.  Doing 10-15 repetition range with shorter rests (30-60 seconds) between sets are suitable to stay within target heart rate.  Since Endomorphs are said to be prone to carry extra body fat, cardiovascular training must be present and regular. If you have not trained for a while, start off easy.

Diet:
We all need to eat frequent yet complete smaller meals rather than 3 large ones.  Endomorphs are no exception to the rule! In fact, they benefit greatly from it as it is said to enhance their metabolism and keep their energy levels more stable. Be sure to eat at least 5-6 meals per day. Meal replacement shakes and bars might help if you are on the go but don't forget to consume "real" food as well.
 
 

The luckiest body type of the three different body types. Called the "gifted" ones.  This type is genetically prone to great muscular gains.  Usually very athletic looking, with good posture and symmetry.  For a bodybuilder or fitness model this is good news.   Mesomorphs are said to build muscle faster than most people and are able to loose fat rapidly when on the right diet.  Where the ectomorph and the endomorph both have a positive and negative side, the mesomorph has the best of both worlds.

Training:
The best type of training is said to be achieved with heavy weight performed explosively (with great force output, intensity). Super sets, Compound sets and giant sets are useful here as they can produce significant gains. Always allow proper recovery, rest and variety as this style of workout can easily lead to overtraining!

Cardiovascular exercises should be done 2-3 times a week for about 20-30 min per session. Intensity wise, moderate to high for fat burning purposes. Don't go over board as it is believed that Mesomorphs could loose lean mass if cardio is too long or frequent!

Diet:
Protein is the key. So be sure to get quality protein daily along with moderate amount of carbohydrates (preferably low glycemic ones) and fat. Ideally, a Mesomorph should avoid weight fluctuation in order to gain or retain mass. Adopting a diet that is rich in nutritious and "clean" food will help you to keep your appetite and energy level stable (satisfied) and avoid cravings.