Portion sizes: Am I eating the right amount? - The Food Chain podcast, BBC World Service

Key Concepts

• Portion Size: The amount of food served or consumed in a single sitting.
• Portion Distortion: The phenomenon where larger serving sizes become the new norm, altering our perception of what constitutes a normal portion.
• Ultra-Processed Foods: Man-made foods, often high in sugar, salt, and unhealthy fats, that are a significant contributor to increased portion sizes and overeating.
• External Cues: Environmental factors, such as the size of a plate or the amount of food served, that influence how much we eat, often overriding our internal hunger and fullness signals.
• Psychology of Eating: The study of how psychological factors influence our eating behaviors, including portion size perception and consumption.
• Americanization of Food System: The global spread of American food trends, including larger portion sizes and the prevalence of ultra-processed foods.

Portion Size Comparison: UK vs. US

The episode begins with a direct comparison of portion sizes between the UK and the US, using takeout from the same fast-food company.

• Chicken Nuggets: The UK participant received 20 nuggets, while the US participant received 40, double the amount.
• Fries: The UK participant's fries weighed 157 grams, containing approximately 90 individual fries. The US participant's fries weighed around 150 grams, indicating similar portion sizes for fries in this instance.
• Sodas: The standard soda size in the UK is 500 milliliters. In the US, the standard size is 800 milliliters, which is double the UK size. The US participant noted that this was not the largest size available, with a "super size" option being even larger.
• Chocolate Cake: The UK participant's chocolate cake weighed 135 grams. The US participant's "extra large" chocolate cake weighed 195 grams, significantly larger.

Expert Insights on Portion Size Trends

Registered dietitian nutritionists Dr. Lisa Young (New York University) and Dr. Marle Alvarenga (University of São Paulo) provide insights into the factors driving increased portion sizes.

The Rise of Larger Portions in the US

Dr. Lisa Young explains that portion sizes in the US began to increase in the 1980s due to several factors:

• Increased Eating Out and Competition: Restaurants competed by offering larger portions, leading consumers to favor establishments perceived as offering better value.
• Cheap Food: When food is inexpensive, manufacturers can increase portion sizes and charge slightly more, creating a perceived "bargain" for consumers and increased profits for the industry.
• Psychology of Eating and "Super Sizing": Fast-food chains like McDonald's and 7-Eleven studied consumer psychology. Offering a single, very large soda (e.g., 64 ounces) was more appealing than selling multiple smaller sodas, as consumers felt they were only consuming "one drink" despite the massive volume. This strategy allowed companies to charge a small premium for significantly more product.

Global Trends and Cultural Influences

Dr. Marle Alvarenga discusses her research comparing US portion sizes with those in Brazil and France.

• Brazil Mirroring US Trends: Brazil, as a developing country, is mirroring US trends, particularly with packaged and processed foods. This includes larger soda bottles, increased serving sizes in fast-food restaurants, and larger popcorn portions in movie theaters.
• Imported Foods: The increase in portion sizes in Brazil is often seen with imported foods from the US, featuring the same brands and selling strategies.
• France: A Different Approach: A study comparing US and French foods found that even the same brands were smaller in France. This is attributed to France's traditional approach to eating, which emphasizes the quality of food and the eating experience. French people spend more time at the table and resist the trend of larger portions.
• Cultural Mentality: Dr. Young adds that American culture values "bigger" (houses, sizes, portions), whereas countries like France focus more on the quality of food and the eating experience. Americans tend to "wolf down" meals without much attention to company or the act of eating itself.

The Role of Ultra-Processed Foods

Both experts highlight the significant role of ultra-processed foods in the portion size issue.

• Problematic Foods: Dr. Young argues that the problem with large portions lies primarily with ultra-processed foods (fast food, candy bars, sodas) rather than whole foods like apples, lettuce, rice, and beans. These man-made foods are often high in sugar, salt, and unhealthy fats.
• Increased Calorie Intake: A 2021 paper by Dr. Young showed significant increases in the sizes of ultra-processed foods like hamburger buns, fries, sodas, and candy bars. Eating larger portions of these foods can lead to an extra 500 calories without conscious awareness.
• Lack of Compensation: Research indicates that people do not compensate for overeating large portions at one meal by eating less at subsequent meals. This means that consuming a large portion at lunch can lead to a net increase in calorie intake over the day.

The Psychology of Portion Size

Professor Lenny Vartanian, an expert on the psychology of eating and weight from the University of New South Wales, explains why larger portions lead to increased consumption.

• Eating More with Larger Portions: A robust finding in research is that people eat more when served larger portions, even if they don't finish everything. A meta-analysis estimated that doubling a portion size leads to people eating 35% more.
• Unreliable Internal Cues: It's difficult to know how much is the "right" amount to eat. Our internal hunger and fullness signals (our guts) are not always reliable, especially in modern environments.
• External Cues as Guides: Portion size acts as a strong external cue, guiding our decisions about how much to eat. When presented with a large portion, especially in a restaurant where we've paid for it, we tend to trust that it's an appropriate amount.
• Food Environment Complexity: The overall food environment is complex for laypeople to understand (calories, macronutrients). We often rely on external sources for guidance, including portion size recommendations.
• Confusing Labeling: Suggested servings on food packaging are often confusing and not well-utilized by consumers, as the concept of a "standard serve" can be context-dependent and not always the only appropriate amount.

Addressing the Portion Size Problem

The experts discuss the challenges consumers face and potential solutions.

• Consumer Blame is Difficult: Dr. Young argues that it's difficult to place the blame on consumers when the environment makes it hard to understand their needs and make informed decisions.
• Need for Better Mechanisms: The food industry and policymakers need to provide clearer information and practical strategies for consumers to manage their intake.
• Packaging Solutions: Professor Vartanian suggests that packaging could be re-engineered to facilitate portion control. For example, resealable packets for snacks or pizza boxes that easily fold in half could help people save leftovers.
• The "Plate" and "Pyramid" Guidelines: Dr. Young notes that dietary guidelines, like the USDA's plate model, have moved away from "recommended servings" to more ambiguous "cup or ounce equivalents." The question of "how much food should we be putting on our plate" is complex and depends on what else is eaten throughout the day and the context of the meal.
• Plate Size Influence: While very large plates can influence how much is put on them, excessively small plates (like those at buffets) can lead to multiple trips and increased consumption. A normal-sized plate (9-10 inches) is generally recommended.
• Rules of Thumb and "Portion Distortion": Traditional rules of thumb (e.g., fist-sized portion of broccoli) are difficult to apply when restaurants serve disproportionately large portions of meat (e.g., 400 grams in Brazil). The concept of "portion distortion" highlights how larger servings shift our perception of normal.
• Advice for Consumers:
  • Awareness: Become aware of what you are eating and the size of portions.
  • Tune into Hunger: Pay attention to hunger and fullness cues, rather than relying solely on external cues.
  • Use Hand as a Guide: Use hand sizes as a rough guide (e.g., palm-sized portion of meat).
  • Slow Down and Eat Consciously: Pause during meals, slow down, and eat mindfully to better gauge your appetite.
  • Re-engineer Home Environment: Make palatable foods less accessible (e.g., avoid large jars of cookies).
  • Look at Labels: Pay attention to food labels and try to understand what is being marketed.

Conclusion

The discussion concludes that portion size is a complex issue influenced by commercial interests, cultural factors, and the psychology of eating. While there are no simple answers, increased awareness, mindful eating practices, and potential changes in food packaging and industry practices are crucial for helping individuals manage their intake and combat the pervasive trend of oversized portions. The experts emphasize that the focus should shift from "portion control" to "portion awareness" and tuning into internal hunger signals.