In today’s market, meal replacements and protein shakes are two types of products widely used by consumers but are often confused. The distinction is important, given that weight management and athletic performance are different goals, and that obesity is a rising problem.
In the past 27 years, not one country has reduced its obesity rate, according to the Global Burden of Disease Study. Obesity prevalence has nearly tripled during the last 40 years. It is only accurate to call this disease an epidemic.
The imbalance between the calories consumed and calories expended, plus the reduction of physical activity due to the increasingly sedentary nature of urban lifestyles, are the fundamental causes of excess weight.
Therefore, a reasonable strategy would be to consciously create opportunities for a more active lifestyle and a healthy diet. However, people often struggle to make the right food choices.
This might be due to:
- Lack of time
- Need to eat outside home
- Increased portion sizes
- The availability, convenience, and taste of high-energy but low-nutrient dense food
This is where meal replacements can be a powerful tool to manage body weight.
What Is a Meal Replacement?
Not to be confused with protein shakes, smoothies or juicing, meal replacements are products intended to replace the nutritional value of a meal but with lower total calorie intake. They include protein along with other nutrients (such as vitamins and minerals) and are often used for weight loss or weight maintenance, with protein to satisfy hunger and manage one’s appetite. Depending on the program, they could be used to replace one or two of the usual three daily meals. A protein shake, on the other hand, is primarily intended to deliver protein and is usually designed to add protein to the diet, not to replace a meal.
As ready-to-eat or easy-to-prepare foods, meal replacements can come in a variety of forms, including meal bars, shakes, and powders that can be mixed with milk. Shakes, in particular, can replace high-fat and high-calorie meals with a measured amount of calories.
Unlike protein shakes or fruit and vegetable juices, a 200- or 300-calorie meal replacement shake provides both macronutrients and micronutrients typically consumed in a typical 500 to 800 calorie meal.
What Constitutes a Meal Replacement?
Research over the last 15 years has demonstrated that using meal replacement shakes to create a calorie deficit is an effective means of weight management recognized by the European Food Safety Authority and the Academy of Nutrition and Dietetics in the United States.
In a study from the University of Ulm, led by Marion Flechtner-Mors, Ph.D, member of the Nutrition Advisory Board at Herbalife Nutrition, participants struggling with obesity underwent an energy-restricted diet and were randomly assigned to either a high-protein diet or a conventional protein diet for 12 months. Protein-enriched meal replacements were used to supplement the diet of the high-protein group.
According to the study, the high-protein group achieved significant weight loss while preserving fat-free mass when treated with an energy-restricted, high-protein diet that included nutrient-dense meal replacements, as compared with the results for conventional protein intake.
The Role of Protein and Fiber in Meal Replacements
Plant-based proteins –like soy– tend to be one of the main ingredients in many meal replacements. In some products, dietary fiber also plays an important role. This combination has a reason for being: both of these components help to manage hunger and appetite.
Hunger and appetite, although sometimes used as synonyms, are not the same. Hunger refers to a physiological need to eat, while appetite is the desire to eat. People may report the desire to eat in the absence of hunger. Apart from physiological factors, the sensorial exposure to food, such as sight, smell, taste, has been shown to increase appetite.
But how exactly do plant-based protein and fiber contribute to satiety?
Protein
- You are most likely to feel fuller after eating protein than other nutrients such as carbohydrate or fat.
- Protein is digested more slowly than carbohydrate, which means it is present in the gastrointestinal tract for a longer time.
- Plant-based and animal-sourced proteins have a similar effect on appetite.
- Soy-based foods are not only a source of high-quality proteins but also a source of fiber.
Fiber
- Fiber slows down the time it takes for food to pass through the stomach and into the small intestine. This helps slow down the absorption of glucose into the bloodstream and keeps you feeling fuller for longer periods of time.
- Fiber fills your stomach, stimulating receptors that tell your brain that it’s time to stop eating.
- To move fiber through your digestive system, you’ll need to drink plenty of water. This helps fight hunger, too, since thirst can often be confused with hunger.
Because protein is such an important ingredient in meal replacements, there is some confusion about whether they are the same as protein shakes. They are not, and you’ll see why.
Meal Replacements vs Protein Shakes: What’s the Difference?
Protein products and meal replacements differ in nutritional composition and are designed for different goals. To put it simply, meal replacements are designed to help with weight control, while protein drinks are more often used for athletic performance and muscle gain.
Confusing a meal replacement shake with a protein shake is a mistake that could interfere with your weight management goals.
Here is an easy way to understand the two:
Meal Replacement Shakes
- Intended to substitute one or two meals of your daily diet.
- Usually fortified with vitamins and minerals.
- They offer more fiber and carbohydrates than protein shakes
- They may have more calories per serving than a protein shake, although they are lower in calories than actual meals.
- Provide protein, but at usually at lower levels than most protein shakes.
Protein Shakes
- Intended to supplement a regular diet, not to replace a meal.
- To be consumed before or after a workout.
- Typically up to 25 g of protein per serving.
- Usually have less than 5 g of carbohydrates, since they are not intended to be full meals.
- Tend not to contain few, if any, added vitamins and minerals other than those provided by the protein source.
Both products have their uses, and as a consumer, it’s important to choose the right product for your specific goal. Protein shakes are great for fueling intense workouts, building, toning and repairing muscle tissue. A meal replacement shake, on the other hand, can help you lose or maintain weight.
David HeberM.D., Ph.D., FACP, FASN – Chairman, Herbalife Nutrition Institute
Dr. David Heber is the chairman of the Herbalife Nutrition Institute (HNI), which promotes excellence in nutrition education for the public and scientific community and sponsors scientific symposia. The HNI Editorial Board is made up of key scientific opinion leaders from around the world in the fields of nutrition, exercise physiology, behavioral medicine and public health. Dr. Heber holds a degree in chemistry, an M.D. from Harvard Medical School and a Ph.D. in physiology from UCLA.* In his spare time, he enjoys golfing, reading and painting. Dr. Heber’s favorite Herbalife products are Formula 1 Healthy Meal Nutritional Shake Mix, Herbalife Personalized Protein Powder and the SKIN product line.
*The University of California does not endorse specific products or services as a matter of policy.