If you're on a diet or just trying to eat healthier, salads are likely a staple of your meal plan. While they're great for filling you up with fibre, to create truly nutritious salads you should also consider the water content of each ingredient.
Many common salad ingredients are high in fibre, but pretty low in nutritional value. Iceberg lettuce, for example, is mostly water. Darker, loosely packed greens like spinach, red leaf or mixed greens are a much healthier — and equally filling — salad base. You should also think about the water content of your other salad ingredients. Other veggies with high water content (like cucumbers, celery and radishes) are some of the least nutritious, and they can easily be replaced with other healthful and still tasty options (like broccoli or carrots, for example).
Why Salad Is So Overrated [The Washington Post]