What are meal replacement shakes, and do they work for weight loss? What about their safety? Are they healthy? Many commercially available shakes are marketed to people as a weight loss aid or for health promotion, but there are several things you should keep in mind before spending money on pricey meal replacements.
- Any way of eating that significantly cuts calories will result in weight loss. Calories aren’t everything, but energy can’t come from nothing. In carefully controlled trials, people do indeed lose more weight when they consume fewer calories over time. In the real world, some diets may be harder to stick to for certain people than others and may not actually change caloric intake very much over an extended period.
There’s no doubt that meal replacement shakes can be effective for losing weight, but so can many other ways of dieting. One way that meal replacements likely help some people lose weight is by being sold typically in low calorie, pre-portioned sizes. Even when given solid foods, people are more likely to reduce the calories they eat when they are given moderate, pre-portioned serving sizes.
Many diets can also “work” for a period of time by restricting which foods people are allowed to eat. Research shows that the less variety of foods people are allowed, the less they eat on average. So, diets that cut out all carbs, all fats, or all solid foods usually get people to eat less overall – though they’re ultimately unsustainable. For weight loss to last, any changes to eating or behavior have to last too. Few people are willing to eat or drink a strictly limited set of things for long periods of time, so highly restrictive diets tend to work in the short run but end up leading to weight regain quickly after the diet ends.
- Different meal replacement shakes can vary dramatically in their contents and quality. Perhaps it goes without saying, but not all meal replacements are the same. Unlike simple protein smoothies or bars, meal replacements should include an array of vitamins, minerals, and a balance of protein, carbs, and fats that are meant to mimic the overall nutrition of a balanced meal.
Not all do, though. Shakes based around protein are often deficient in carbs, healthy fats, fiber, and phytonutrients (like certain antioxidants and anti-inflammatory molecules found in whole plants). Fruit- and vegetable-based meal replacements, such as the juice-based drinks many people consume on a fast or cleanse, are often deficient in healthy fats, protein, calories, and sometimes fiber. It’s common to not get everything your body needs from a shake no matter how many nutrients are listed on the label. It’s also healthiest for the body and mind to get over 1,000 calories each day even when trying to lose weight. Eliminating all solid foods may leave people too low in energy or nutrients, so it’s wise to include at least some whole food in any meal plan.
Whole plant foods, in particular, have nutrients besides minerals, vitamins, proteins, and fats that are vital for good health. Few shakes have all the necessary nutrients that a balanced meal has. If possible, go for shakes with several fruits and vegetables plus more than 15 grams of protein and at least four grams of unsaturated fat.
- Meal replacement shakes are often pricey, but they do offer convenience. Even simple protein shakes aren’t cheap calorie-for-calorie, and meal replacement shakes tend to be much more expensive than protein shakes. Many products seem to justify the cost by offering some type of proprietary “superfood” blend, or a mix of vitamins, fiber, amino acids, fats, or other things.
One thing shakes do offer is convenience; it’s easier to drink a shake than to prepare a meal. For weight loss, some people prefer not to think much about food and nutrition. Relying on a simple formula of “three shakes a day” or something similar may help some people stay focused. The same problem of sustainability comes in here though, as few people are able to drink only shakes or to restrict most other foods for the long periods of time required to keep extra weight off. Balance is a central principle in nutrition, and including meal replacement shakes for convenience sometimes may work well, provided they keep you full and offer decent nutrition. Just remember that including at least some whole foods is an important part of the equation too.
- Consider what type of program is sustainable for you personally. Weight loss, or any type of behavioral change, is more like a marathon than a sprint; for real success, it’s not about how fast you can go but how long you can sustain. Different ways of eating can work well for different people depending on their schedules, their level of interest in cooking, their personal preferences, and so on.
I wouldn’t recommend one specific way of eating for everyone, though there are a few things that we know tend to help people stay healthy and stick with their meal plan over time. Eating balanced meals regularly is one helpful factor, so I would look at meal replacement shakes as a tool to possibly help supplement one’s diet when balanced meals aren’t available. One risk factor for overeating and gaining weight back is skipping meals, so the convenience of shakes could help some folks stay on track when they’re in a tight spot.
Learn more about Structure House’s nutritional approach and how it can help you reach your goals.