Following a protein shake diet encourages weight loss by curbing appetite and reducing the total calories a person consumes in a day. Healthcare professionals do not recommend living solely or primarily on protein shakes.
Protein helps build muscle and plays a vital role in cell function across the body.
Protein needs will vary from person to person based on their weight and activity levels. Usually, a person can easily obtain the amount they need from the diet by consuming beans, lentils, nuts, meat, eggs, and dairy products.
Protein shakes aim to provide as much protein as food but with fewer calories. Some can even provide more protein than food. The idea is that replacing meals with protein shakes can improve weight loss and muscle gain.
Although these diets can be effective in the short term, healthcare professionals do not recommend prioritizing meal replacement shakes over a balanced diet.
In this article, we explain how the diet works, ways to follow it safely, and what protein shakes can do to benefit overall health.
Protein shakes offer more than just protein. Manufacturers typically fortify them with a range of vitamins and minerals. They may also contain fruits, vegetables, and other nutrients.
A small 2025 study linked high protein consumption at breakfast to increased feelings of fullness in comparison to high carbohydrate consumption at breakfast. People who include enough protein in their diets may therefore have fewer food cravings and eat less. Some may choose to get this protein through shakes.
The sections below discuss protein in more detail.
Benefits of protein
Most protein-rich foods provide a wide variety of vitamins and minerals. Several of these nutrients — including B-complex vitamins, iron, choline, and zinc — are
Other vital nutrients that some protein-rich foods provide significant amounts of include:
How does protein work in the body?
Protein supports
It also helps the body create hormones and enzymes and metabolize vitamins. It is an essential part of a well-balanced and nutrient-dense diet that encourages good health.
Several companies offer diets that mainly feature protein shakes. For this reason, the requirements and offerings of each program vary. Some diets are more extreme, encouraging participants to eat only or primarily protein shakes.
However, the most balanced protein shake diets include protein shakes as part of a diet that is rich in other food sources.
For instance, the diet might recommend replacing one or two meals with a protein shake, then eating one or two different meals that also provide nutritional benefits, as well as snacks.
A well-balanced diet should always include an appropriate amount of protein, nutrient-dense carbohydrates, and unsaturated fats.
Meal replacement shakes should not completely replace healthy, balanced diets. This is because it is difficult to get every nutrient from a single food source.
Furthermore, a body that does not receive enough nutrients may experience problems with metabolism. This may slow or disrupt a weight loss plan. In fact, a 2025 review found that people who eat a varied diet, such as the Mediterranean and DASH diet, may have better metabolic health outcomes.
Some protein shakes also use large quantities of sweetener to improve flavor, which can trigger blood sugar spikes.
It is also important to avoid consuming too much protein powder in one day. A 2020 review noted that, over time, high protein intake may have adverse effects on kidney function. Therefore, a person may want to consider speaking with a healthcare professional about how much protein to include in their diet based on their individual health and lifestyle factors.
As nutritional supplements, protein shakes are subject to fewer regulations than medication in the United States. Therefore, the marketing materials for these products may also be misleading.
A 2020 study noted that some past reports have indicated that some protein powders have detectable levels of heavy metals such as:
However, the study authors highlighted that typical intake of protein powders is unlikely to cause adverse health effects due to heavy metal ingestion.
Instead of protein shakes, a person may want to consider prioritizing protein-rich foods such as milk, lean meats, and eggs, in the diet.
Medical PerspectiveCan people drink more protein shakes if they are also working out?
“Whether a person drinks more protein shakes if they are working out depends mostly on their overall pattern of dietary intake.
“If they are consuming plenty of quality protein from whole and natural food sources then protein shakes are probably unnecessary, but if they are relying heavily on protein shakes to meet their daily protein needs, they may drink more than they may otherwise need to consume.
However, this possible overreliance on protein shakes should be avoided if quality food sources are accessible.”
— Jared Meacham, PhD., RD, CSCS
Learn more about how to calculate protein intake based on age, activity level, and more.
Quotes represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.
Protein consists of amino acids, and the most nutritious proteins are “complete.” This means that they contain all nine essential amino acids.
Most protein shakes use one or more of the following six varieties:
- whey protein
- casein protein
- egg white protein
- soy protein
- plant protein
- beef protein
To get the most out of a protein shake diet, a person may want to consider talking with a doctor or registered dietitian first. People should only consume one or two protein shakes daily and for a short time only.
Protein shakes should be part of a balanced diet. For instance, a person who does not eat many vegetables might choose a meal replacement protein shake that contains vegetables.
One way to enhance weight loss when following a protein shake diet is by eating nutrient-dense, low-calorie foods between shakes. Eggs, lean meats, lentils, fruits, and vegetables are excellent foods to eat to round out a protein shake diet.
While a protein shake diet may encourage weight loss in the short term, healthcare professionals do not recommend prioritizing protein shakes over a balanced diet.
Most of the time, people can get all the protein they need from whole foods in their diet.
People may want to consider speaking with a doctor or registered dietitian to learn more about incorporating nutritious sources of protein into their diet.