368 ‒ The protein debate: optimal intake, limitations of the RDA, & whether high-protein is harmful

The prevailing Recommended Dietary Allowance (RDA) for protein is insufficient for optimizing health and performance, with current evidence suggesting higher intake (1.6 to 2.0 g/kg) is generally beneficial and safe for most individuals, while the concept of 'ultrarocessed' foods is considered a less meaningful heuristic than focusing on molecular composition.

• The 0.8 g/kg protein RDA is a survival minimum, not optimal for thriving, with 1.6-2.0 g/kg recommended for muscle, strength, and health.

• The impact of food on health is primarily determined by its molecular structure and chemical composition, not whether it is categorized as 'processed' or 'ultrarocessed'.

• Traditional public health approaches have largely failed to combat obesity, highlighting a need for radically different strategies, possibly including broader societal improvements and pharmaceutical interventions.

The discussion challenges the conventional protein RDA of 0.8 grams per kilogram of body weight, arguing it is merely a survival minimum and inadequate for goals like muscle maintenance, physical performance, or preventing sarcopenia. A higher intake, typically ranging from 1.6 to 2.0 grams per kilogram, is suggested as more optimal for thriving, with no compelling evidence of harm in healthy populations. Additionally, the concept of 'ultrarocessed foods' is critically examined, with the argument that the chemical composition and molecular structure of food are more important than its processing history or categorization for understanding health effects.

Protein Intake Debate

• 00:01:20 The hosts delve into the contentious debate surrounding protein intake, noting a historical pattern of 'demonizing' different macronutrients, now extending to protein. This shift is attributed to food's deep connections to culture, economics, and identity, driving emotional and sometimes irrational discussions. The current focus on protein sees a fever pitch of enthusiasm from some sectors, contrasted by skepticism and efforts to 'poo-poo' or minimize its importance from others.

RDA Origins and Limitations

• 00:04:04 The discussion highlights the origins of the ubiquitous 0.8 grams of protein per kilogram of body weight RDA, tracing it back to early nitrogen balance studies. These studies, primarily conducted on lean, inactive young men, aimed to determine the minimum intake for survival and preventing wasting, not for optimal health or specific performance goals. Consequently, the RDA is seen as a 'base level' or 'economy rental' for protein, insufficient for individuals aiming to thrive, build muscle, or recover from injury.

Trustworthiness in Science

• 00:13:36 The hosts address concerns about conflicts of interest in nutrition science, distinguishing between being 'trusted' (a judgment from others) and 'trustworthy' (related to scientific processes). They emphasize that in science, three things matter for trustworthiness: the data, the methods used to collect data, and the logic connecting data to conclusions. Everything else, such as ad hominem attacks or innuendo, is considered tangential and irrelevant to the scientific validity of an argument.

Challenges in Nutrition Science

• 00:16:06 Nutrition science faces significant methodological and social challenges that make it fraught with difficulties. Methodological issues include the expense and complexity of collecting precise human dietary data, the long duration needed for outcome studies (like longevity), and the inability to blind or randomize all aspects of diet. The social aspect involves the emotional, economic, and cultural influences that often lead to deviations from logic and personal attacks in discussions about food.

Optimal Protein Intake

• 00:31:01 For individuals seeking to optimize health beyond basic survival, such as avoiding sarcopenia, enhancing physical performance, or improving body composition, a protein intake higher than the RDA is recommended. Evidence suggests that intake in the range of 1.2 to 1.6 g/kg, and even up to 2.0 g/kg, offers significant benefits for body weight, appetite control, bone strength, and muscle, particularly for older adults, growing individuals, and those engaged in physical activity. There is no compelling evidence of harm for healthy individuals at these higher levels.

Limitations of Epidemiology

• 01:00:42 Epidemiological studies in nutrition are often limited by several biases, including confounding by socioeconomic status and culture, non-random measurement error in self-reported food intake, and selection biases. A significant concern is the 'opportunity cost' – the substantial funding spent on large epidemiological studies that could instead support more rigorous randomized controlled trials. While not entirely invalid, epidemiological data often provide weak inference and leave open alternative explanations for findings beyond causation.

Critique of Processed Foods Classification

• 01:25:02 The distinction between 'processed' and 'ultrarocessed' foods is critiqued as an arbitrary social construct, lacking a single, universally accepted scientific definition. Most foods consumed daily undergo some form of processing, and many processed foods offer benefits like safety and shelf-life. The classification system (like NOVA) is controversial, and focusing on these categories can be a 'heuristic' that oversimplifies the actual effects of food on health. The true impact of food is determined by its molecular structure and chemical composition, not its ancestry or processing history.

Public Health Solutions for Obesity

• 01:49:16 Current public health strategies have largely failed to address the metabolic health crisis, unlike the success seen in smoking cessation. The inherent difference is that individuals can stop smoking entirely, but not eating. Public health efforts for obesity have often focused on 'obvious' but ineffective interventions like school programs or calorie labeling. A more radical approach, focusing on general education, financial security, and good parenting rather than nutrition-specific education, is hypothesized to have long-term benefits in reducing obesity and diabetes. The future may also involve widespread use of highly effective pharmaceuticals like GLP-1 agonists as a default intervention.