Can I Lose Weight by Only Drinking Protein Shakes?

Can I Lose Weight by Only Drinking Protein Shakes

There are two opposing groups in the world of weight loss: there is the protein shake loving bunch, treating their protein shakes like the Holy Grail and there are the naysayers that say protein shakes are harmful supplements and cannot work as weight loss products.

You can lose weight by only drinking protein shakes, but the effects might be short-lived. Protein shakes curb your appetite and lower your calorie consumption. But since a protein-shake-only diet is not sustainable, you could gain all the weight lost when you resume your normal eating habits.

In this article, we’ll help you understand the science of weight loss, outline the benefits that proteins bring to the weight loss process, and explain why some people are so wary about an over-reliance on these supplements for weight loss. Read on.

The Science of Weight Loss

A protein-shakes-only diet will encourage weight loss as long as you observe strict dietary guidelines. Your “meal-in-a-bottle” could help cut those pounds down because, as fitness instructors say, “abs are not made in the gym, they’re made in the kitchen.” In other words, you cannot out-exercise a poor diet.

Exercise only helps in weight loss if you burn more calories than you eat. Unfortunately, most people overestimate the efficacy of their workout regime. They often burn fewer calories than they think.

As an illustration, a 5′ 10″ (177.8 cm) 154-pound (69.8 kilos) man will only burn 480 calories after an hour of vigorous aerobic exercises. A pre-made burger can easily deliver 460 calories! Should this man leave the gym and head for the grill?

You can easily cancel those tireless efforts at the gym with a single meal. Stay on top of your relationship with food, and you will win the battle of the bulge.

A good long-term weight loss and maintenance menu should have ample vegetables, fruit, and lean proteins. It should also have whole grains, healthy fats, and a regular exercise routine.

Why Do Protein Shakes Help in Weight Loss?

Have you heard of the protein leverage hypothesis? Human beings are collectively becoming overweight because, like other omnivores, we have a ‘dominant appetite’ for protein.

According to Professor David Raubenheimer of the University of Sydney, birds, insects, monkeys, pigs, cats, and slime mold all have this condition.

The nutritional ecologist says that if you eat a carbohydrate-rich, low protein diet, you will gulp down more heavy carbs in search of more protein. The professor adds that humans have a rigid daily protein target that has remained unaltered by time.

Unfortunately, people are now eating much more carbs and fats than they did 50 years ago. The good professor argues that protein is the forgotten element in the ongoing battle against obesity.

According to the protein leverage hypothesis, take your focus off the grams of protein on your plate. Review, instead, the ratio of protein in your diet.

Weight loss is not just about cutting calories but having the right macronutrient balance. Should you cut down on your calorie intake and not hit your protein target, you will cave into the resultant hunger pangs and eat more cheap carbs. This is the reason high protein-shakes-only meals work.

This hypothesis could explain our collective devotion to pork ribs and roast chicken. It also explains why this macronutrient is vital to the weight loss equation. Science says that proteins boost metabolism. Their amino acid loaded composition builds muscle mass and reduces appetite.

They also affect the body’s weight-regulating hormones and will make your body look better.

Break protein down, and it will increase your metabolism and muscle mass creation.

One other important attribute of protein is the effect of its intake on the brain. The hypothalamus is the part of the brain that actively regulates weight.

Your brain will respond to feeding hormones to determine how much food you should eat, and when you should eat it. When you take protein-rich food, you will feel fuller and reduce ghrelin levels (the hunger hormone).

Replacing fat and carbs with protein will boost the satiety hormones, minimizing the feeling of hunger. This science makes a protein shake only diet effective for short-term weight loss.

Here’s a summary of the weight loss benefits of a protein shake diet:

  • Increase in muscles mass and improved physical performance
  • Promotes weight loss by helping you sustain a high daily protein intake
  • Increasing the feeling of fullness and delaying the emptying of the contents of your stomach
  • Increasing the calories that the body burns and boosting your metabolism
  • Promoting the oxidation of fat leading to fat loss

More Info: Here are the Best Protein Shakes to Help You Lose Weight

Types of Proteins in Shakes

While foods such as milk, meat, eggs, legumes, and poultry contain a lot of protein, powders and shakes are a high-quality source of protein. They sell these supplements as liquids, capsules, and powders that you can mix with water or any other liquid to complement your diet.

These drinks can be very handy for people trying to hit their daily protein targets or those that do not have high-quality sources of protein at hand. Some proteins in them include:

  • Dairy-based casein protein with all essential amino acids
  • Dairy-based whey protein, which is quickly absorbed and has all the essential amino acids
  • Plant-based hemp protein a rich source of omega-3 and -5 fats but a low source of essential amino acids such as lysine
  • Plant-based pea protein low in non-essential amino acids such as methionine and cystine
  • Plant-based rice protein, low in essential amino acids such as lysine

While there are brands that will go for one protein source, some mix the plant-based protein sources with the dairy-based ones to enhance the protein shakes’ amino acids profile.

Are Protein-Shakes-Only Diets Harmful?

Most dieticians do not advocate for protein shakes only diets unless taken under medical supervision. Chemical-free high protein drinks are prescribed for people that have difficulty eating or those that have an impaired appetite because of disease or frailty.

A person with surgical incisions or with a health condition that requires more protein for healing, such as burn victims, could have more protein drinks in their diets. According to a Harvard Health Letter, some veiled dangers of protein shakes and powders are:

  • Protein powders are supplements, so the FDA leaves the safety and the labeling of the product’s ingredients to the manufacturer.
  • According to the US department of health guidelines, adult males need 56 grams (1.97 ounces) of protein, while women need 46 grams (1.62 ounces) of protein per day. There could be yet to be proven long-term effects of extremely high protein intake from protein shakes.

There is, however, a direct correlation between high-saturated animal fat protein-rich diets and kidney stones, colon cancer, and heart disease.

  • Some protein shakes have high amounts of sugars in them, as high as 23 grams (0.81 ounces) per scoop. This could translate to a 1200-calorie rich meal per glass, spiking your blood sugar and increasing your body’s weight.
  • Some of these supplements are high in toxins and heavy metals such as lead, mercury, cadmium, and arsenic. These contaminants could cause cancer.
  • A protein shake only diet is not sustainable in the long run. Protein shakes should only supplement or replace a meal, not your entire regime. Since a shake only diet is unmanageable for months on end, you could gain all the weight lost when you resume your normal meal schedule.
  • Your meals and snacks should be nutritionally balanced for a strong and healthy body. Your protein shakes will not offer a well-rounded, balanced diet.


We live in a protein manic age. Proteins are like a secular balm that makes any food product healthy. This worship of protein is not baseless. Eating and drinking protein shakes helps with muscle and injury recovery and weight loss.

That said, the key to long term sustained weight loss is a balanced, healthy diet and physical activity.

Looking for a Healthy Protein Source? I highly recommend Shakeology because it uses a high quality whey protein and plant proteins to better fulfill your needs.

Beachbody Shakeology shakeAs mentioned above, you want to be careful with your protein powder because many can have harmful chemicals. With Shakeology, however, you’ll get a nutrient dense shake made from whole foods that include the following nutrients:

  • Protein
  • Superfruits & Antioxidants
  • Prebiotics & Probiotics
  • Adaptogens
  • Supergreens & Phytonutrients
  • Vitamins & Minerals

Because of all the nutrients in Shakeology, you will lose weight because you will feel fuller longer than only drinking a regular protein shake.

Check out my full Shakeology Review Here



Before using meal replacement shakes and exercising, I was obese and on track to having high blood pressure at the age of 25. I'm glad to say I lost 50 pounds and am living a healthier lifestyle than before. Now I like sharing what I learned when I first researched what meal replacement to drink and the best way to lose weight. Learn more about me here...

Recent Posts