The Skinny on Meal Replacements for Weight Management
Today's Dietitian
By Dawn Jackson, RD, LD
Vol. 6 No. 7 p. 12

Meal replacements can be successful weight- management tools. Will the mealtime experience be left in the dust? Read the pros, the cons, and the research.

I confess: I use meal replacements with many of my weight-management patients. “I cannot believe that you recommend those things to patients” are words that I have heard from both patients and fellow dietitians. Comments like this made me wonder: Are meal replacements a weight-management tool dietitians can recommend with a clear conscience? Are meal replacements a healthful food choice or just a short-term solution to a chronic condition? Who benefits from using meal replacements? How should patients be instructed to use meal replacements?

What Is a Meal Replacement?
Meal replacements include beverages, prepackaged shelf stable and frozen entrees, and meal/snack bars. The majority of meal replacements are vitamin- and mineral-fortified and designed to replace one or two regular meals or snacks per day. Meal replacements are found in conventional grocery stores, health food stores, and even small convenience stores. The market of these ready-to-eat meals is booming, and many new companies and products are on the shelf every month. Meal replacements are widely used by consumers, but should dietitians formally use these types of meals with patients to facilitate weight loss?

What Are the Pros?
The advantages of meal replacements include convenience, price, variety of tastes, portion/calorie control, and, often, improved nutrition. Meal replacements are convenient in both access and preparation; they are widely available and require little or no preparation or cooking. While meal replacements do vary in cost, most are reasonably priced for every budget.

Research studies using meal replacements have found high approval ratings for both taste and appetite satisfaction.1 Meal replacement entrees are sold in a variety of flavors and styles, and they offer portion- and calorie-controlled comfort foods and old favorites. Deborah Caldwell-Stone, who lost 130 pounds in 13 months and is now maintaining her weight, attributes her success to meal replacements in addition to regular exercise. “Meal replacements enable me to enjoy my favorite foods, such as fettuccine alfredo, without penalty and without feeling deprived or guilt,” says Caldwell-Stone.

Americans suffer from “portion distortion”; most people do not know proper portion sizes.2 Meal replacements not only provide portion-controlled, calorie-controlled foods, but also serve as visual portion reeducation. “Meal replacements were not only a shortcut to portion control, but also a means of retraining my stomach and my eyes to identify proper portions,” says Caldwell-Stone. “After a few weeks with meal replacements, my stomach resized itself.”

Cathy Nonas, MS, RD, CDE, is the director of diabetes and obesity at North General Hospital in Harlem, N.Y., and is the editor of Managing Obesity: A Clinical Guide. Nonas uses meal replacements in her practice “because they are easy to find, inexpensive, and provide simplified calorie and portion control.” Nonas believes using meal replacements often improves the nutrition of her patients. Research on nutrition adequacy of meal replacements found that individuals’ nutrient profiles were maintained or improved for most nutrients while using meal replacements. Meal replacements can improve food choice behavior and nutrient adequacy.3 See Table 1 for a nutrition comparison of self-selected meals vs. meal replacement meals.

What Are the Cons?
“Meal replacements do not contribute to a long-term solution to weight management,” “they are nutritionally inadequate,” and “they are too small to be realistic and satisfying” are some of the arguments against the use of meal replacements. Katherine Tallmadge, MA, RD, is the author of Diet Simple and president of Personalized Nutrition. She, like many other dietitians, does not believe there are any advantages to using meal replacements.

Tallmadge says that meal replacements do not teach people how to eat “real food,” lose weight, or keep weight off successfully. She does not recommend meal replacements because she believes they encourage people to eat too quickly and have less enjoyment of their food. “I don’t want to encourage bad habits like downing foods quickly and on the run,” she says. “I find people do better when they learn to respect their mealtimes, sit down, slow down, relax, and enjoy their meals as much as possible.”

Although research would indicate meal replacements maintain or improve nutrient profiles of a diet, some dietitians are concerned that meal replacement eating plans could lead to nutritional inadequacies. Meal shakes, bars, and frozen entrees are often thought of as processed foods that are high in sugar, salt, and preservatives. Although many meal replacements are vitamin- and mineral-fortified, there are still many with no fortification.

The one thing that does concern Nonas about meal replacements is that “for some people, meal replacements don’t satisfy them long enough.” This was not the case, though, in Caldwell-Stone’s experience. “I try to eat slowly and intentionally, and the meals tend to be very satisfying, especially when paired with a salad or fruit,” she says.

What Is the Research?
There are noted pros and cons to using meal replacements, but what does the research indicate about them? Do they work to facilitate weight loss and maintenance? A thorough review and analysis of the meal replacement literature was published in the International Journal of Obesity in 2003.4 The reviewed studies compared meal replacement diet plans (249 participants) with conventional reduced-calorie diets (238 participants). In the meal replacement groups, participants were prescribed a low-calorie diet whereby one or two meals were replaced with commercially available, energy-reduced products that were vitamin- and mineral-fortified and included at least one meal of regular foods. The control group was prescribed a conventional reduced-calorie diet composed of patient-selected foods. The prescribed calorie intake was the same for both groups.

The overall weight loss at three months in the meal replacement group was 7% of initial body weight compared with the reduced-calorie diet group, which was approximately 4%. At one year, the results in the meal replacement group were a loss of 7% to 8% of initial body weight compared with the reduced-calorie diet group at approximately 3% to 7%. A 5% reduction in body weight is clinically significant to improve health outcomes. At both three months and one year, approximately 74% of the meal replacement group had lost and maintained a 5% or greater weight loss compared with only 33% of the reduced-calorie group. Overall, weight loss in the meal replacement groups was greater than that observed in the patient-selected, reduced-calorie diet groups. Even in studies carried out to four years, groups using meal replacements consistently had greater weight loss than reduced-calorie diet groups.5

In addition to weight loss, other metabolic factors have shown improvement with the use of meal replacements. Improvements have been noted in fasting glucose levels, total cholesterol, and low-density lipoprotein (LDL) cholesterol.6 Studies have also shown that the use of meal replacements can decrease cardiovascular risk as seen by reductions in systolic and diastolic blood pressure and total and LDL cholesterol.7 Other biological markers that have shown improvement with the use of meal replacements include triglycerides and insulin.

Are Meal Replacements Recommended in Clinical Guidelines?
Meal replacements are not mentioned in the “Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults—The Evidence Report,” prepared by the National Institutes of Health,8 but they are mentioned in the “ADA Position Paper on Weight Management”9 as a possible tool for weight control. There are no formal guidelines written on the use of meal replacements in clinical practice. So, what type of patient would benefit from meal replacements, and how should they be instructed to incorporate them in their eating plans?

Anyone can use meal replacements. They have been shown to improve metabolic markers for diabetes and heart disease.5,6,7,10 Many people recruited in meal replacement research studies were dissatisfied with a standard energy restricted diet plan that they had been following and claimed difficulty adhering to changed eating habits after several attempts in a diet program.5,11 This may indicate that meal replacement plans are appropriate for use especially in individuals who have been treated with traditional self-selected reduced-calorie diets without success.11 The greater compliance with meal replacement diets vs. self-selected food plans is believed to be a result of a more structured meal plan that reduces the number of decisions required for food choices and may help prevent unintended dietary failures.10

Nonas recommends patients use meal replacements “for lunch with fruit or a vegetable salad with measured dressing.” Sometimes she suggests them for dinner “if that is the meal that is most out of control and if they live alone.”

In many of the research trials, meal replacements are used to replace two meals per day for initial weight loss (approximately three months) and one meal per day with the weight-maintenance phase (from one year to four or more years). Some studies instruct patients to use two meal replacements per day until they lose 10% of their initial body weight and are then instructed to use only one meal replacement per day thereafter. If weight is regained, patients are then instructed to reinitiate the use of two meal replacements per day until they lose the weight.12

Whether it is one or two meals replaced with meal replacement products, the remaining meal(s) should be low in fat, rich in fruits and vegetables, and average approximately 600 to 900 calories. Between meals, snacks should include vegetables, fruits, or replacement snack bars; each snack should provide approximately 100 calories.10 It appears that two meal replacements per day promote weight loss, whereas one meal replacement per day appears to be sufficient for weight maintenance.11

“I recognize that meal replacements can be seen by many people as a kind of ugly, overprocessed food crutch,” says Caldwell-Stone, “but I think they are a good tool for a person struggling to start or maintain a weight-loss program. Meal replacements gave me quick, positive results to encourage me to stick with my eating plan.”

So, yes, I use meal replacements with many of my patients. Although both advantages and disadvantages exist, many people can benefit from using meal replacements for both weight loss and long-term weight maintenance. While I agree that not everyone is a candidate for using meal replacements, they can be one of many important tools for weight management.

— Dawn Jackson, RD, LD, is a national media spokesperson for the American Dietetic Association and a practicing dietitian at Northwestern Memorial Wellness Institute in Chicago.

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