59 pages • 1 hour read
Peter AttiaOutlive: The Science and Art of Longevity
Peter AttiaNonfiction | Book | Adult | Published in 2023A modern alternative to SparkNotes and CliffsNotes, SuperSummary offers high-quality Study Guides with detailed chapter summaries and analysis of major themes, characters, and more.
Part 3, Chapters 14-15Chapter Summaries & Analyses
Part 3, Chapter 14 Summary: “Nutrition 3.0: You say Potato, I say ‘Nutritional Biochemistry’”
In Chapter 14, Attia underscores that we know very little about nutrition and diet:
Nutrition is relatively simple, actually. It boils down to a few basic rules: don’t eat too many calories, or too few; consume sufficient protein and essential fats; obtain the vitamins and minerals you need; and avoid pathogens like E. coli and toxins like mercury or lead. Beyond that, we know relatively little with complete certainty (296).
In fact, he does not believe that nutrition can improve healthspan and lifespan in the same way as exercise (which goes against conventional wisdom). Rather than using the term “diet,” he prefers the term “nutritional biochemistry” or Nutrition 3.0, which places discussions about nutrition “back into the realm of science” (294).
Attia argues that nutrition research is poor quality. There are two types of nutrition research. The first is epidemiology, or when researchers gather data from a large group of people and extrapolate the results to the population level. Attia takes issue with epidemiology for two reasons. The first is that epidemiology cannot distinguish between correlation and causation. Correlation is when there is a statistical association between variables. Causation means a change in one variable causes a change in another. Importantly, correlation does not mean there is causation, which often causes confusion among the public about study findings. It is also nearly impossible to determine causal relationships about nutrition because “factors that determine our food choices and eating habits are unfathomably complex” (300). Researchers cannot distinguish biochemical food effects from these factors, such as socioeconomic background, religion, and education. Despite this, epidemiology studies are always in the news, leading to greater confusion and contradictions about what people should and should not eat and drink.
The second reason Is that epidemiological studies are based on data collected from study participants. Attia notes that “humans are terrible study subjects for nutrition (or just about anything else) because we are unruly, disobedient, messy, forgetful, confounding, hungry, and complicated creatures” (298). This means that the raw data that informs study findings is inaccurate and messy, which makes our findings inaccurate and messy.
The second type of nutrition research is clinical trials, where “one group of subjects eats diet X, the other group is on diet Y, and you compare the results” (302). In contrast to epidemiology, researchers can infer causality through clinical trials due to the randomization process. Attia still believes clinical trials have flaws. It is difficult to have a large study group that lasts for a long period of time because researchers need to watch the group to ensure they are following the instructions. Compliance in clinical studies (and nutrition more broadly) is a serious issue, which skews results.
Attia concludes that nutrition research will always be flawed because nutrition impacts everyone differently. Thus, we can never generalize about diets. Attia hopes people make eating plans that work for them, which is the subject of Chapter 15.
Part 3, Chapter 15 Summary: “Putting Nutritional Biochemistry Into Practice: How to Find the Right Eating Pattern for Your Brain”
Attia’s goal in this chapter is to help people break free of the standard American diet (SAD), characterized by ultra-processed junk food, and find the best, more natural eating plan for themselves. He focuses on three strategies, including their strengths and weaknesses: caloric restriction (CR), dietary restriction (DR), and time restriction (TR).
To Attia, CR, also known as calorie counting, means “eating less in total, but without attention to what is being eaten or when it’s being eaten” (309). As Attia meticulously documents in Part 2, eating too many calories makes people more susceptible to the Horsemen diseases. Moreover, laboratory research on rats and mice suggests eating fewer calories lengthens chronological lifespan. People who adhere to CR must meticulously count their calories. This tracking often makes this strategy unfeasible. This strategy is also agnostic to food types. However, Attia cautions that consuming too much junk food will negatively impact a person’s metabolic health (although they could in theory lose weight). Attia concludes that limiting calories might be helpful for overnourished or metabolically unhealthy individuals. However, he cautions against extreme caloric restrictions because of its unwanted side effects, such as constant hunger, muscle loss, and weakened immune system. Long-term studies on primates suggest that a high-quality diet might be enough for someone who is metabolically healthy and not overnourished.
Attia defines DR as “eating less of some particular element(s) within the diet (e.g., meat, sugar, fats)” (309). DR is a highly individualized plan, since people can restrict certain foods depending on their needs. However, Attia cautions against fad diets that follow DR, such as low-carb or ketogenic diets, due to individual metabolisms. Attia argues that “the real art to dietary restriction, Nutrition 3.0-style, is not picking which evil foods we’re eliminating. Rather, it’s finding the best mix of macronutrients for our patient” (320). He recommends manipulating four macronutrients: alcohol, carbohydrates, protein, and fat.
TR focuses on “restricting eating to certain times, up to and including multiday fasting” (309). There are three types of fasting. The first comprises short-term eating time spans. The second is alternate-day fasting (ADF), which is where you alternate between eating as usual and eating very little. The final type is hypocaloric where “you are eating just enough to quell the worst hunger pangs, but not so much that your body thinks you are fully fed” (245). Attia underscores that the health benefits of fasting in scientific literature are still weak. The loss of muscle mass and reduced activity levels for people who follow TR also concerns Attia. While he once practiced fasting and recommended it to his patients, he now believes it is best to use for people who have the most severe metabolic dysfunctions.
Part 3, Chapters 14-15 Analysis
In these two chapters, Attia continues to bust myths related to health to illustrate The Failures of Modern Medicine (Medicine 2.0). Conventional wisdom holds that fats are bad and can be removed from the diet. However, this perspective is not true. Due to chemical structure, there are three types of fat: saturated fatty acids (SFA), monosaturated fatty acids (MFA), and polyunsaturated fatty acids (PUFA). All three fat types are found in foods that contain fat. Thus, people cannot remove one of these fat types from their diet. Moreover, fats also serve as fuel for the body. Rather than trying to restrict fats, Attia advocates for tweaking the ratios of these fat types in a person’s diet. This can be done by looking at the results of an expanded lipid panel.
Attia also presents several studies that highlight the complexities of nutrition research. Two were long-term studies on rhesus monkeys. These studies were published within a few years of one another. One study found that a reduced calorie diet resulted in longer lifespan for the monkeys, whereas the other found the opposite conclusion. Initially, these studies seemed to present contradictory results, yet digging deeper into the findings told a more nuanced picture. One study fed monkeys poorer-quality food. Thus, those in the calorie-restricted group likely survived longer than the control group because they were eating less of the poorer-quality food. In contrast, the other study fed their monkeys higher-quality food, so severe caloric restrictions did in fact lead to differences in mortality rates. This study is important for two reasons. The first is that it shows nutrition research is extremely complex and nuanced. The second is that it emphasizes the importance of quality over quantity when it comes to diet.
Attia also highlights the dangers of SAD (Standard American Diet). SAD represents a mismatch with our evolutionary environment. Our ancestors evolved in an environment where they faced famine. As such, we evolved “to be highly efficient fat-storage vehicles” (308) since this would allow us to survive periods with little food. There is now ample food, much of which is high-calorie and nutrient-poor. For this reason, the Horsemen diseases are inflicting havoc on American families. Attia notes that “SAD essentially wages war on our metabolic health, and given enough time, most of us will lose the war” (309).
Ultimately, this section presents the levers readers need to manipulate to create a meal plan that works for them. Of particular importance is the ability to manipulate the four macronutrients. Attia considers alcohol a macronutrient because it is calorically dense, widely drunk, and has a strong impact on metabolism. He firmly believes that people should consume far less alcohol for three reasons: it has no nutritional benefits, it causes people to overeat, and it slows fat oxidation.
Of the four macronutrients, carbohydrates cause the most confusion because there are so many conflicting studies on whether they are good or bad. Attia suggests using a tool called continuous glucose monitoring (CGM) “to help us understand our own individual carbohydrate tolerance and how we respond to specific foods” (323), although it is only currently available by prescription. Medicine 2.0 practitioners do not accept the widespread use of CGM for non-diabetics due to high costs and lack of research showing its benefit to weight loss. From his years of using CGM, Attia gained 10 valuable insights, including that more refined carbs cause higher spikes of glucose (which is bad), sleep, stress, and exercise all impact glucose control, and nonstarchy vegetables and foods high in protein and fat have little impact on blood sugar.
Protein is an important macronutrient since it represents “the essential building blocks of life” (330), helping us to build and maintain muscle mass and promote metabolic health. Attia believes people should be consuming more than the US recommended daily allowance (RDA). In fact, he believes it is nearly impossible for someone to consume too much protein. People can consume plant protein and protein supplements, but they need to understand their protein quality score.
Similar to carbohydrates, there is a lot of confusion surrounding fat, in particular because of its caloric density and role in heart disease via raising LDL cholesterol. However, fats are essential building blocks and sources of fuel. Attia notes, “eating the right mix of fats can help maintain metabolic balance, but it is also important for the health of our brain, much of which is composed of fatty acids” (335).
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