People still believe that having a low fat high carbohydrate diet is healthier and better for body composition.. Are carbohydrates essential to life? NO! I don't know about you but I never heard of an 'Essential Sugar', or an 'Essential Glucose Acid'. However, the other two macro nutrients, protein and fats are essential. We have essential amino acids and we have essential fatty acids. These are not called essential for no reason. They are called 'essential' because the body cannot produce them itself. Carbohydrates are purely a fuel source. They have not been proven to aid protein synthesis and you don;t even need to consume carbs to produce glucose.
We eat carbohydrates as they are palatable, easy to cook and prepare and easy and cheap to get hold of. Glucose will be stored and eventually used for fueling our activities. But why would you want to use glycogen to fuel your activity, surely you want to burn fat right? Without eating carbs, your body is clever enough to break down other substances to use as fuel such as stored fat (ideally) or amino acids (not ideal). This is called gluconeogenesis, where a non-carbohydrate form is broken down and utilised as fuel. Not only this, but our muscles release lactate that can be converted to glucose in the liver and used as a fuel source if needs must during prolonged exercise. So 1. we can convert other substances to use as fuel and 2. our body can make glucose without even eating carbs!
Benefits of eating higher fat over higher carbohydrate dieting:
#1 You will be less hungry on a higher fat diet.
#2 Higher fat diets lead to less risk of cardiovascular disease and heart problems
#3 Improves metabolic flexibility
#4 Improves Insulin Sensitivity (ability to store glucose in the muscle and not as fat)
#5 You will burn fat at rest
#6 It will reduce your cravings for higher glyceamic foods
#7 You will have better brain function and improved mood because your brain is made up mainly of cholesterol and essential fatty acids.
#8 Better HDL/LDL Cholesterol Ratio and can lower blood pressure.
#9 Stronger immune system due to forms of saturated fats killing dangerous pathogens.
#10 Higher fat diet will stabilize your blood sugar, meaning you wont get crashes and extreme tiredness/fatigue. (Also helping to reduce risk of diabetes)
Conclusion: for optimal body composition, base your diet around fats and protein. Not only are carbs non-essential, but our bodies can produce glucose in other ways. For some performance purposes, for the top level athletes, carbs may be necessary, but then they are very conditioned to know how to use and what to do with the glucose that it will not effect their body composition.