Unlike protein shakes, meal replacement shakes are intended to provide the nutrition of a full meal ().
Some come prepared in a can or bottle, while others come in a powdered form that can be mixed with milk or water.
Most meal shakes contain 200–400 calories and a good amount of protein, fiber and essential vitamins and minerals.
For this reason, meal replacement shakes are a convenient way to get a healthy, low-calorie meal on the go.
However, their ingredients and nutrient compositions can vary substantially, with various proportions of protein, carbs and fat.
Here is a complete overview of whether or not these shakes help with weight loss.
Meal replacement shakes are portable and convenient, and they may help you resist the temptation to indulge in unhealthy processed foods.
In fact, one of the biggest barriers to losing weight is the time it takes to prepare healthy meals.
When you are stressed or in a hurry, it's much easier to grab a processed convenience food or give in to fast food.
Unfortunately, typical processed foods can seriously derail your weight loss efforts.
Most are full of sugar, refined carbs and artificial ingredients, in addition to lacking beneficial nutrients.
Furthermore, processed foods that are high in sugar, salt and fat activate the pleasure centers of the brain, which can also lead to overeating (, , ).
Conversely, meals made from healthy, whole foods are best for losing weight, but that is not always practical with a busy schedule.
Meal replacement shakes are easy to drink on-the-go and a significantly healthier alternative to fast foods.
Bottom Line: Meal replacement shakes are convenient. They're also a healthier alternative to fast foods.
Meal replacement shakes are designed to provide all of the nutrients that you should consume in a complete meal.
When you cut back on calories, it can be difficult to get all of the nutrients you need from your diet.
Shakes are often fortified with nutrients, which might fill your nutrient gap while you are cutting back on calories.
The best meal replacement shakes contain protein, fiber and essential vitamins and minerals.
For example, many commercial shakes are a good source of nutrients such as calcium, potassium, iron and vitamin D, which many people are lacking in their diets.
Bottom Line: Since meal replacement shakes provide all the nutrients you should be consuming in a meal, they can help you meet your nutrient needs while cutting calories.
Reducing your calorie intake is key to losing weight.
However, sticking to a low-calorie diet can be challenging, especially if you end up feeling hungry.
Meal replacement shakes can help you feel full while consuming fewer calories ().
Several studies suggest that replacing one or two meals per day with a healthy meal replacement shake may speed up weight loss (, , ).
One analysis found that participants following a partial meal replacement diet plan lost 5.6 more pounds (2.4 kg) in three months than those following a food-based, reduced-calorie diet ().
Interestingly, fewer people following the meal replacement plan dropped out of the studies. This might be because it was easier to follow.
Moreover, one review found that four out of seven studies reported significantly greater weight loss with meal replacements than a traditional diet. Yet, the other three studies found no difference in weight loss ().
Also, one study found that those consuming a meal replacement shake lost the same amount of weight as those consuming a low-fat, low-calorie, controlled diet (10).
Furthermore, some studies have found that meal replacement shakes boost weight loss in diabetics.
In one study, liquid meal replacements led to 1–2% greater weight loss in obese subjects with type 2 diabetes than a diet based on the diabetic exchange system ().
Those consuming the meal replacements also had lower fasting blood sugar and LDL cholesterol levels ().
Another study found that meal replacement shakes in those with type 2 diabetes contributed to slightly greater weight loss than conventional dieting ().
Meal replacement shakes may also help with weight maintenance after weight loss has been achieved ().
Bottom Line: Meal replacement shakes may be useful for reducing calorie intake and boosting weight loss.
Not all meal replacement shakes are the same.
Nevertheless, many are high in protein, which is one of the most important nutrients for weight loss.
Higher protein diets lead to greater satiety, which can help you eat fewer calories throughout the day (, , , ).
One study found that men on a high-protein diet reported fewer cravings and a reduced desire to eat late at night than those consuming a moderate amount of protein ().
Furthermore, high-protein diets have been associated with other benefits, such as increased lean body mass, reduced body fat, less belly fat and improved weight maintenance (, , , , ).
In a study comparing high-protein meal replacements and high-carb meal replacements, both groups lost similar amounts of weight in 12 weeks ().
However, those in the high-protein group lost more body fat, and their "bad" LDL cholesterol levels were lower ().
Lastly, some meal replacement shakes are higher in protein than others, so choose a shake that is high in protein and low in sugar.
Bottom Line: Meal replacement shakes that are high in protein may help you lose weight and body fat.
There are several benefits to using meal replacement shakes to lose weight.
They are convenient for busy lifestyles, and they are helpful for people who struggle to limit their food intake.
However, there are some potential problems with meal replacement shakes.
Some Contain Unhealthy Ingredients
Plenty of meal replacement shakes are made with wholesome ingredients.
Others contain unhealthy ingredients like added sugars, corn syrup, partially hydrogenated vegetable oils, artificial flavors and chemical preservatives.
Look for a high-protein shake that also contains fiber and a list of ingredients you can pronounce. A healthy meal replacement shake should contain no more than a few grams of sugar.
They May Not Be a Long-Term Solution
Meal replacement shakes may not be a long-term solution for weight management.
While many brands of meal shakes provide important nutrients, they cannot completely replace a healthy diet full of whole foods.
In addition to vitamins and minerals, whole foods contain antioxidants, plant compounds and enzymes that are difficult to put into a bottle.
Some shakes do contain fiber, although significantly less than the amounts found in whole foods like fruits, vegetables and legumes.
Additionally, drinking shakes for meals is not a sustainable lifestyle for many people. It can be a socially isolating practice, since many social events include food.
They Don't Fix Unhealthy Eating Habits
In general, diets don't work for weight loss. Long-term weight loss requires long-term lifestyle changes.
While drinking meal replacement shakes can help you lose weight, they don't force you to change your eating habits.
If you simply go back to your old eating habits when you stop replacing your meals with shakes, you will likely regain the weight.
Bottom Line: Meal replacement shakes are convenient, and they may help you lose weight. However, they may not be a long-term solution for healthy weight maintenance.
To choose the best meal replacement shake for weight loss, ignore the claims on the front of the package and read the ingredient list on the back.
Choose a product with the following qualifications:
- At least 15 grams of protein per serving
- At least 3 grams of fiber per serving
- Less than 10 grams of sugar per serving
- No corn syrup
- No hydrogenated vegetable oils
- At least 33% of the Daily Value for vitamins and minerals
There are several different types of protein used in meal replacement shakes.
Whey protein has been found to improve satiety and is a good ingredient to look for in a meal replacement shake ().
You can also make your own meal replacement shakes at home. There are endless combinations of ingredients, but here is one recipe to try:
- 1 cup unsweetened almond milk
- 1 cup frozen berries
- 1 tablespoon coconut oil
- 1 cup plain Greek yogurt
- 1–2 scoops whey protein powder
Mix all ingredients together in a blender until smooth. This homemade shake contains approximately 400 calories, 30 grams of protein and 30 grams of carbs.
Bottom Line: Some meal replacement shakes are healthier than others. Choose a shake that is high in protein and low in sugar.
Meal replacement shakes are a portable and convenient option for an on-the-go meal. They may be an effective way to reduce your calorie intake and lose weight.
However, be sure to choose a meal replacement shake that is high in protein and low in sugar and artificial ingredients.