As you probably know, nutrition is of the utmost importance for achieving
results in your fitness program and living a healthy life in general.  Like
exercise, nutrition must be goal specific.  If you want to lose weight you
cannot eat a high Calorie diet.  If you want to gain weight you cannot eat a low
Calorie Diet.  No matter what your goals are, here are the most important tips
for active people to consider about their diet.
You cannot take a once size fits all approach when it comes to nutrition.
It does not matter if you read a diet in a magazine or have an expensive
nutritionist for your nutrition program.  What works for other people may not
work for you.  To find what works for you, experimentation is a must.  I stress
eating for variety.  The more variety of food and fluids you consume, the more
satisfied you will be with your meals.  Consuming a variety of foods, the more
vitamins, minerals, antioxidants, and phytochemicals you will get in your diet. 
Far less negatives such as saturated fats, simple sugars and excess calories
will be consumed.
 Having proper nutrition will allow you to achieve optimum and more rapid
results in any training program.  Nutrition cannot be overlooked when optimum
athletic performance is considered as well. 
Eating Healthy Food and Fluids is More Important than Calorie Counting 

Many diets and nutrition programs focus strictly on calories in their
program.  This is definitely NOT the best way to approach your diet.  Consuming
the optimal foods will more than likely take care of the calories for you.
Most commonly referred to “clean" foods are better for satisfying your hunger
and giving you the nutrients for energy for exercise.  “Clean" foods are
generally natural, nutrient dense foods without added fats and sugars.  The
healthier the food is blatantly obvious some times.   If you had the choice
between macaroni & cheese or plain sweet potato you can plainly see which would
be better for your health. Steamed vegetables or fries?  This is never really
difficult.
Eating 5-6 small Meals and Snacks Takes Care of Food Timing
Have you ever been told not to eat, or not to eat or not to eat carbs after
6pm?  This is something that is not good.  Eating 5-6 small meals and snacks
evenly spread out through the day is optimal.  This will not only take care of
your pre- and post- exercise meals but will also keep your energy levels stable
throughout the day.  When your body is constantly breaking down smaller
portions, your energy, metabolism and fat burning will speed up.
 Be a Cheater!
Sometimes sticking to a diet is very difficult.  This is why cheating on your
diet once in a while will keep you on track.  If you are accustomed to cheating
on your diet once a week you will be less likely to binge the next time you see
a pizza, cookies or chips sitting in front of you.  Cheating simply means eating
an “un-clean" high calorie food that is not a normal part of your diet.  Save
this meal for a social occasion and don’t overdo it.
I hope you find my advice useful.  I have much more but it would take
hundreds of pages.  The advice I want you to remember is if it does not work for
you, move on to something that may.  Einstein once defined insanity as doing the
same thing over and over again and expecting different results.  Good luck and I
hope you are in the best shape of your life soon.