Macronutrients reflect the 3 groups that we can place food into.  Note, this does not tell us whether the food is healthy or not. Example, both a lollipop and carrot can be considered a carbohydrate.  The first point of call is always to source natural and nutrient dense food before making a fuss about macros.

Carbohydrates - Fuel

Too Much - Rollercoaster blood sugar levels, bloating or excessive farting and gain body fat.

Too Little - Low energy, digestive blockage.

Ideal - Consistent energy levels, regular stool cycle, not dependent on 'sugar hits'. Avoid refined options.

Protein - Structure & metabolism

Too much - Digestive blockage and weight gain.

Too little - Higher risk of stress, injury and breakdown and muscle loss.

Ideal - Balanced satiety (not hungry / full) and lean muscle mass.  Pursue quality free range sources.

Fat - Fuel and nutrient (fat soluble) absorption

Too much - Weight gain.

Too little - Feeling hungry, cognitive degeneration and low HDL cholesterol. 

Ideal - Consistent mental clarity and energy levels, able to go 5 hours without feeling hungry, naturally sourced options.