What is a meal replacement product?

What is a Meal Replacement?

Meal replacements are discrete foods, food products, or drinks specifically designed to replace one or more regular meals with the intent to reduce daily energy intake for weight loss or weight maintenance. 1

Definition and Key Characteristics

Meal replacements (MR) have several distinguishing features:

• They are formulated to replace one or more daily meals while maintaining at least one conventional food meal per day 1
• They provide a fixed-energy, portion-controlled option that typically contains less energy than self-selected meals 1
• They are available as various product formats:
  • Bars (most common form) 2
  • Powder for making shakes 2
  • Ready-to-drink beverages 2
  • Crackers or other solid formats 2

Distinction from Total Diet Replacement (TDR)

It's important to distinguish meal replacements from total diet replacement programs:

• MR replaces one or two meals daily while maintaining at least one conventional food meal 1
• TDR products replace all meals and snacks as the sole source of nutrition 1
• MR can be purchased over the counter without prescription, while TDR programs are typically advised to be undertaken under supervision 3

Nutritional Composition

Meal replacements typically provide:

• Average energy content of approximately 266 kcal per meal 2
• Macronutrient distribution of approximately:
  • 45% carbohydrates
  • 29% fats
  • 26% proteins
  • 4.45 grams of fiber 2
• Fortification with vitamins and minerals, often providing at least 33% of Recommended Dietary Allowances (RDA) per meal 2
• Particularly high levels of iron and vitamins B1, B6, and D 2
• Often lower levels of calcium, magnesium, folic acid, and vitamin B12 2

Efficacy for Weight Management

Meal replacements have demonstrated effectiveness for weight management:

• People using MR diets lose an additional 1.44 kg at 1 year compared to conventional diets 3, 1
• When combined with behavioral support, MR diets result in 2.22 kg greater weight loss compared to supported conventional diets 3, 1
• Weight loss benefits appear to be maintained for up to 4 years 3, 1
• MR programs increase the proportion of participants achieving clinically significant weight loss (≥5% and ≥10% of initial weight) 3, 1
• Studies show similar effectiveness whether replacing one or two meals per day 4

Mechanisms of Action

Meal replacements work through several mechanisms:

• Provide fixed-energy, portion-controlled options 1
• Contain less energy than most self-selected meals 1
• May improve overall nutritional quality of the diet 1, 5
• Simplify dietary choices, potentially improving adherence 2

Clinical Applications

Meal replacements can be useful in various clinical contexts:

• As part of comprehensive weight loss programs 3, 6
• For patients with obesity and comorbidities like osteoarthritis 4
• For improving cardiovascular risk parameters (HOMA-IR, systolic blood pressure, total cholesterol) 4
• As a strategy to ensure adequate nutrient intake during caloric restriction 5

Limitations and Considerations

Important considerations when using meal replacements include:

• Long-term evidence beyond 4 years is limited 1
• Quality and nutritional composition vary significantly between products 1, 2
• Must be continued indefinitely if weight loss is to be maintained 3
• Not consistently recommended in many national obesity management guidelines 1

Safety Profile

Research indicates that meal replacements are generally safe when used as directed:

• No reported adverse events attributable to meal replacement regimens in clinical trials 6
• May help ensure more adequate essential nutrient intake compared to traditional food-based diets during caloric restriction 5