Meal replacements are solid, liquid or powdered foods intended to partially or totally replace daily meals. The integration of meal substitutes into the diet often aims to lose weight quickly. Be careful, however, there are a very large number of substitutes on the market and not all are equal.
Characteristics of the diet based on substitutes for losing weight:
- Induces a weight loss of about 1 kilo per week
- Provides accurate and consistent food intake
- Substitutes are consumed in parallel with a more or less complete diet
- Relatively low-fibre diet high in sugars and saturated fats
The main principles of the regime
There are many diets based on meal replacements. While some suggest replacing only one or two meals (and sometimes snacks) with substitutes, others recommend replacing all meals.
How does the meal replacement diet work?
Meal replacements were originally designed to help hospitalized people whose illness prevented them from eating solid food and the desire to eat. This type of product still exists and is sold in pharmacies under different brands for the hospital sector. But the food industry quickly discovered that they could be used to control caloric intake in overweight and obese people, resulting in a wide range of weight loss alternatives. Today, many of them can be found in pharmacies and health food stores.
Meal replacements are generally made from protein (skim milk powder, whey protein or soy protein isolates), carbohydrates (sugar, dextrose, sorbitol, honey, glucose syrup or glucose-fructose), fat (vegetable oil, hydrogenated palm oil or soya lecithin) and vitamins and minerals. There are also colours, artificial and natural flavours and preservatives. More natural meal replacements have emerged in recent years, but they are not the most popular or widespread. These products are available in powder, liquid or bar form. They generally contain 180 to 300 calories, 12 g to 20 g of protein, 0 g to 10 g of fat, 10 g to 40 g of carbohydrates and 0 g to 3 g of fibre per serving.
Most weight loss programs with meal substitutes recommend following a pre-determined menu (including substitutes) that normally has a total calorie content of 1,200 to 1,500 calories per day, although some reach up to 2,200 calories. In these menus, some meals are composed of food and others of meal substitutes accompanied by fruits or vegetables. Some programmes also recommend following the principle of “food combinations”, i.e. not combining meat and bread in the same meal, for example. Once the desired level of weight loss is achieved, it is generally recommended to maintain your weight by replacing a meal with a substitute on a daily basis.
How does the powdered meal replacement diet help you lose weight?
Meal replacements are supposed to be balanced in terms of macronutrients and relatively low in calories. Their consumption makes it possible to reduce calorie intake without suffering from hunger and, at the same time, to lose weight. In some programs, it is argued that the accuracy of the calorie content of substitutes is preferable to a diet that only seeks to limit portion sizes. Programs that use bar meal replacements claim that a solid substitute increases the duration of satiety compared to a liquid substitute. As with many other diets, it is calorie deficiency that leads to weight loss. It has been shown that by reducing the amount of calories you consume, whether with food or meal substitutes, you can lose weight. It also appears, according to a scientific study, that subjects who follow a diet plan with meal substitutes and regular meals lose more weight in the short term, compared to subjects who follow a conventional low-calorie diet.
How long does the shake meal replacement diet last?
It is not recommended to follow this type of diet for too long. Indeed, even if some substitutes may seem complete, there is no substitute for a healthy and varied diet. Therefore, it is not advisable to get into the habit of consuming this type of product for more than one month.
Foods allowed and foods prohibited in the substitute diet
There are no strictly speaking prohibited foods in the meal replacement diet. It all depends on the method chosen and the context. However, we know that, as with all diets, some foods will help with weight loss. While others will be able to stop it. Here is a list of foods to choose and those to avoid in the meal replacement diet:
|Preferred foods||Foods to be limited|
Typical one-day menu with meal replacements
slices of wholemeal bread10
|Lunch||120 g chicken cutlet150|
g brown rice200
with red fruit coulis
|Snack||30 g wholemeal cereal150|
ml skimmed milk or soya
Advantages and disadvantages
The positive points of the meal replacement diet
- Good protein intake
- Sense of satiety
- Requires little cooking
- Easy to follow
- Fast weight loss
The negative points of the regime
- Often too low in calories
- Isolates and rarely allows to maintain a fulfilled social life
- Difficult to maintain over the long term
- Risk of deficiencies and weight gain
- Dangerous for vulnerable people, can create obsessive eating behaviours
Recommendations and precautions to be taken
Are there any risks?
There are several risks associated with this type of diet:
- The consumption of substitutes can cause crises of excess food to meet psychological needs and the absence of gustatory pleasure
- Some meal substitutes contain hydrogenated oil and trans fats that we absolutely must limit
- Some meal substitutes have a very sweet taste, which can maintain the attraction of sweetness
- Most meal replacements do not contain enough nutrients, such as antioxidants found in plants (phytonutrients)
- Most meal replacement diets do not offer gender and height variations, which may create too high a caloric deficit for some people
- Promoting beauty more than health, many weight loss programs with meal replacements recommend cellulite treatments and other cures. These programs are quite expensive and the effectiveness of these treatments has never been proven
- Meal replacements contain very little fibre, which can lead to gastrointestinal problems such as constipation
Is this a diet for you?
Unless medically indicated, the use of meal substitutes is not recommended. To lose weight permanently, nothing beats a varied and balanced diet.
Is it a diet compatible with sport?
Yes, it is recommended to include physical activity in any diet. Playing sports helps to slow the muscle loss often induced by too rapid weight loss. It also makes you feel better in your body and supports your nutritional efforts.
How can I not gain weight?
This is quite difficult to say since there is no such thing as a substitute regime, but a multitude of them. Overall, to avoid the yo-yo effect, it is better not to replace more than one meal a day with a substitute and to quickly return to a natural and balanced diet.
Organic, high-protein, sugar-free meal substitutes: what is the best meal substitute?
The choice of meal replacement must be made according to the needs of the organization and the context. In general, it is advisable to opt for organic substitutes and without added sugars. Be careful also with the fibre content, which is often very low and could cause digestive problems. For the protein content, be careful not to exceed 25% of the total energy intake of protein. Beyond that, it would be counterproductive and dangerous.
A few figures to go further
According to the conclusions of an analysis of six studies, diets with meal replacements are effective and safe for weight loss and for improving risk factors for overweight-related diseases. Based on the results of these studies, a meal replacement diet has been shown to be as effective as a calorie-restricted diet in weight loss. Participants in the alternative group would even have said they would prefer this diet to the calorie-restricted one. It must be said, however, that psychological satisfaction and taste pleasure have not been assessed. In addition, these studies are often funded by those who market meal replacements (Unilever, for example). It is therefore very difficult not to see a certain causal link. In another study, also sponsored by Unilever, researchers observed that meal replacements can be used successfully to maintain weight over a two-year period.
Meal replacement plan: Our opinion
Losing weight with meal replacements seems effective in the short term, but there is no evidence of their long-term effectiveness or safety, i.e., over a period of at least five years. In my opinion, meal replacements are denatured foods that do not respect the psychological and physiological needs associated with the act of eating. In addition, they do not change eating behaviours or develop new healthy habits, such as buying healthy foods and preparing healthy meals. If human beings were totally devoid of a sense of taste (which is far from being the case!), these products might have their place. But since this is not the case, I believe that in the long term, they can cause more harm than good. I would therefore urge caution if you wish to start this type of food program based on meal replacements.
Also read: Chrononutrition