Are you making this mistake with your green smoothie?

Green smoothies are a trend that is still going strong. It's easy to hide spinach or kale in a smoothie and get those greens in at breakfast, packing a powerful nutritional punch.

However, as creatures of habit, I find that most women use the same green every day- a handful of spinach, or a handful of kale. Are you guilty of this?

Instead, you should vary the greens you take in every day, for multiple reasons.

First, some greens, including spinach, swiss chard and beet greens, are high in oxalates, which bind to minerals and make it difficult to absorb the iron and calcium, and have also been linked to kidney stones. Don't stop eating them- but avoid them every single day. Spacing these greens out to 2-3 times per week is ideal.

Greens that are lower in oxalates include kale, romaine, arugula and all lettuces.

Second, the body craves variety! Alkaloids, a compound found in most plants, can become a problem in concentrated amounts from the same food, and have been shown to even create some intolerance to that food over time. Mix it up!

Third, your cravings will also appreciate variety. The more you can change the flavors in your food and green smoothies, the more your body will enjoy each meal and feel satisfied, instead of craving foods that might not offer nutritional benefits.

If you are a daily smoothie drinker, it's a great way to pack in solid nutrition! Make sure you are balancing the carbohydrates from the fruit and vegetables with some protein, either in the form of a protein powder, yogurt or a with a side hard boiled egg or other protein for a balanced meal.

Balance keeps your blood sugar from spiking, satisfies your appetite for longer, and keeps you on track for a day without crazy cravings and energy spikes.

There are endless combinations and versions. Here's one green smoothie option: