Low carb diets are grounded in the idea that less insulin production (which is linked to a rise in blood sugar levels) means less storage of fat. This is because insulin does indeed cause your body to store extra calories as fat. The result? Low carb diets can cause you to lose weight, especially at first.

What’s the problem with this diet? It’s because low carb diets are tough to remain on, and also because most of these diets claim you can eat as much as you want without regard to portions. Your body needs carbohydrates for energy; it’s very taxing on your system to extract energy from a low-carb diet, forcing your body to take energy from your fat and muscles. And yes, your body will indeed take some of the fuel it needs for daily functioning from your muscles if you are on a low carb diet, especially if you don’t lift weights or perform other forms of muscle-building exercise.

What part of this diet is worth holding onto? The diet highlights the fact that Americans tend to eat too many carbs, especially in the form of refined sugar and starches, so limiting carbs is a good idea—to a certain extent. However, your body needs carbohydrates if you are to perform well athletically, so a low or no carb diet will leave you feeling lethargic, which makes it difficult to fulfill the exercise part of your fitness plan.

What is the healthy option? Limit your carbohydrate intake, eating complex carbs instead of simple carbs as much as possible. Increase your consumption of fruit, vegetables, protein, and fatty fish. Add exercise into your weight loss effort so you will tone and build muscle, not lose muscle. Contol portions and calories by limiting portions and choosing wisely.

This is the kind of weight loss plan you want: something sustainable over time.