If you’re considering a diet of drinking protein shakes and eating fruit -- to the exclusion of everything else -- you need to take certain factors into consideration. Following such a regime could put you at risk for nutrient deficiencies, so it's vital you plan your meals properly to make them as nutrient dense as possible to avoid potential side effects.
Protein's Effect on Weight Loss
Protein is often considered the key macronutrient in a weight-loss diet because of its thermic effect. Thermic effect refers to how many calories you burn off digesting the food. Protein's thermic effect is around 25 to 30 percent, compared to 2 to 3 percent in fats and 6 to 8 percent in carbohydrates. Consuming a higher protein intake may be beneficial for weight loss.
The amount of protein you need depends on the type of training you do and on your goals. The average woman needs 46 grams of protein per day and the average man needs 56 grams, according to the Centers for Disease Control and Prevention. If you’re training, your needs increase. You should aim for 1.4 to 2 grams of protein per kilogram of body weight, or 0.6 to 0.9 gram per pound per day, recommends the International Society of Sports Nutrition. Protein shakes can be a convenient way to meet an elevated intake.
Drinking shakes to bump up your protein intake is OK, but forgoing whole foods in favor of shakes is a dangerous route. Many protein sources contain a host of healthy nutrients. Oily fish, for example, contains omega-3 fats that you don't get in shakes. Likewise, beans and legumes are good sources of fiber, whereas shakes contain practically no fiber. Therefore, eating a piece or two of fruit with every shake is one way to ensure that you get more vitamins, minerals and fiber than drinking only shakes.
Proceed With Caution
Approach carefully any diet that restricts or eliminates whole foods or food groups. Rather than opting for shakes and fruit, a better option may be to have a protein shake and fruit snacks each day, with two meals of a whole-food protein source, such as chicken, eggs or cottage cheese, served with vegetables, whole grains and healthy fats. Include a variety of fruits and vegetables and consult your doctor before making any dietary changes.