Introduction
In "100 Million Years of Food," Stephen Le takes us on a fascinating journey through the history of human eating habits. The book explores how our diets have evolved over millions of years and how this evolution impacts our health today. Le argues that understanding our ancestral diets can provide valuable insights into modern nutrition and help us make better food choices.
The book comes at a time when diet-related diseases are on the rise in the Western world. More people than ever are suffering from type 2 diabetes, obesity, food allergies, and various forms of cancer. Le suggests that by looking back at the diets of our ancestors, we might find some answers to these modern health problems.
The Insect-Eating Origins of Our Diet
Our story begins about 100 million years ago with our earliest ancestors. These tree-dwelling creatures lived in tropical forests and had a diet that would seem quite strange to us today: they primarily ate insects.
The Benefits of Bug-Eating
Believe it or not, insects are actually a great source of nutrition. They're rich in calories, vitamins, and iron. In fact, Le suggests that even today, adding some insects to our diet could be beneficial. Insects are much more environmentally friendly to produce than traditional livestock. For example, crickets produce about 50% less carbon dioxide than cows per pound and are 12 times more efficient at converting feed into edible calories.
Why We Can't Go Back to a Bug-Based Diet
However, Le cautions against trying to adopt a fully insect-based diet like our ancestors. Over time, we've lost the ability to digest chitin, the substance that makes up insect exoskeletons. Eating too many insects could also trigger allergies or expose us to harmful toxins.
The Fruitarian Phase
Around 60 million years ago, our ancestors started to move away from insects and towards fruit. This shift coincided with climate changes that led to the emergence of fruit-bearing trees. Interestingly, it was around this time that our ancestors lost the ability to synthesize vitamin C, making fruit an essential part of their diet.
The Dangers of Too Much Fruit
While fruit was a crucial part of our ancestors' diet, Le warns against going overboard with fruit consumption today. Fruit contains fructose, which our bodies can only process in limited amounts. Overconsumption of fructose can lead to insulin resistance and even pancreatic cancer. Le shares the cautionary tale of actor Ashton Kutcher, who ended up in the hospital with pancreatic issues after following Steve Jobs' fruitarian diet for just a month.
The Rise of Meat-Eating
About two million years ago, our ancestors made another significant dietary shift. As they moved out of the trees and onto the ground, they began hunting and eating more meat. This change had a profound impact on human evolution.
The Brain-Boosting Power of Meat
Le explains that the increase in meat consumption coincided with a rapid growth in brain size. Over the course of just one million years, our ancestors' brain size doubled. This growth was likely fueled by the fatty acids found in meat, which are excellent brain food. Bigger brains gave our ancestors an evolutionary advantage, allowing them to become better hunters and providers.
The Downsides of Excessive Meat Consumption
However, Le cautions that too much meat can be harmful. Our bodies can only process a limited amount of protein, and excess protein consumption can lead to the buildup of toxic nitrogen compounds. Additionally, the high cholesterol content in meat can contribute to clogged arteries when consumed in excess.
On the other hand, cholesterol isn't all bad. It's necessary for the production of essential sex hormones and can improve our moods. Le notes that girls on cholesterol-rich diets tend to reach sexual maturity earlier, which could lead to more offspring but also reduced life expectancy.
Meat Substitutes Throughout History
As humans spread across the globe, different cultures developed various alternatives to red meat. Fish became a popular option in many coastal areas, providing a rich source of omega-3 fatty acids and vitamin D. However, not all cultures embraced fish, with some considering them sacred or unclean.
The Introduction of Milk
Another significant meat substitute emerged about 8,000 years ago: animal milk. Northern European nations were among the first to adopt milk consumption, appreciating its nutritional value and the fact that an animal could be milked multiple times.
The Milk Controversy
Despite its popularity, Le suggests that milk might not be as healthy as we've been led to believe. While milk consumption is linked to increased growth in children, it may come at the cost of bone health. Interestingly, people from regions with little history of dairy consumption tend to absorb calcium more efficiently, which can lead to dangerously high calcium levels if they consume too much milk.
The Reluctant Shift to Plant-Based Diets
Contrary to what many might assume, humans didn't start eating plants because they were particularly healthy. In fact, Le points out that most plants are actually unhealthy and many can be dangerous.
Plants' Chemical Warfare
Plants have evolved various chemical defenses to discourage animals from eating them. For example, some vegetables contain bitter substances, while beans and lentils have chemicals that can make us sick if consumed in large quantities. Le even mentions that one of the most lethal poisons known to man, ricin, comes from a plant.
The Necessity of Agriculture
So why did humans start farming and eating more plants? Le explains that it was largely out of necessity. Around 12,000 years ago, many large animals that humans had hunted, like mammoths, became extinct. With these major food sources gone, humans had to find alternatives. Plants were readily available and could be easily produced, making them the logical choice.
The Impact of Rapid Dietary Changes
While the human body is adaptable, significant dietary changes can take many generations to adjust to. This became a problem when food processing began to become widespread, leading to the emergence of new diseases.
The Rise of Nutritional Deficiencies
Le shares the story of beriberi, a disease that affected wealthy people in East and Southeast Asia in the late 19th century. It was caused by a B1 deficiency resulting from the consumption of highly polished rice. Similarly, pellagra became common among poor populations in the American South around 1900 due to a diet based on industrially milled corn, which lacked vitamin B3.
Modern Lifestyle and Allergies
Le also discusses the rise of asthma and food allergies in modern times. He suggests that our indoor lifestyles, which limit our exposure to sunlight and vitamin D, might be partly to blame. Another theory, known as the hygiene hypothesis, proposes that growing up in overly clean environments prevents our immune systems from developing properly.
Rethinking Calories and Weight
Le challenges some common beliefs about calories and weight. For instance, he points out that Japanese people consume fewer calories on average than Americans, but this doesn't necessarily mean their diet is healthier.
The Downsides of Calorie Restriction
While calorie restriction can lead to longer life, it can also cause problems like reduced fertility in women and difficulty concentrating. Le suggests that it's about finding a balance rather than simply minimizing calorie intake.
The Benefits of Being Slightly Overweight
Surprisingly, Le reveals that being slightly overweight (with a BMI between 25 and 30) is associated with longer life expectancy. This extra weight might provide protection against toxins and serve as an energy reserve during severe illnesses.
The Calorie Myth
Le also challenges the idea that calorie intake is the primary determinant of weight. He cites research showing that modern hunter-gatherers consume about the same number of calories as the average American, despite being slimmer. This suggests that other factors beyond just calorie intake play a role in determining weight.
The Importance of Personalized Nutrition
One of the key messages of Le's book is that there's no one-size-fits-all approach to nutrition. What's healthy for one person might not be for another, depending on factors like age, heritage, and individual physiology.
The Alcohol Example
Le uses alcohol as an example of how dietary needs can vary. While moderate alcohol consumption can have heart health benefits for people over 40, many people of Asian descent need to be cautious due to a genetic predisposition that makes them more sensitive to alcohol's effects.
Age-Related Dietary Changes
Le also points out how dietary needs change with age. For instance, while a high-meat diet might cause early puberty in young girls (potentially increasing cancer risk), it could be beneficial for elderly women by increasing their strength.
The Social Aspect of Eating
Despite the individual nature of nutrition, Le emphasizes the importance of communal eating. He reminds us that our ancestors used to hunt together and share food, which strengthened community bonds and ensured fair distribution of resources.
Bringing Back Communal Eating
Le suggests that we should try to make meals more communal in our modern lives. This could be as simple as sharing more meals with friends or supporting pay-what-you-can restaurants. By doing so, we can reintroduce an element of care and community to our eating habits.
Key Takeaways from 100 Million Years of Food
Our Ancestral Diet: Our earliest ancestors primarily ate insects, which are nutritious but no longer suitable as a primary food source for humans. Later, our ancestors shifted to a fruit-based diet, and then to one that included more meat.
The Impact of Meat: Increased meat consumption likely played a role in the rapid growth of human brain size. However, excessive meat consumption can lead to health problems.
Plant-Based Diets: Humans turned to agriculture and plant-based diets out of necessity when large game animals became scarce. Many plants have evolved chemical defenses against being eaten.
Rapid Dietary Changes: The rapid shift to processed foods in recent history has led to new nutritional diseases and deficiencies.
Weight and Calories: Being slightly overweight might actually be beneficial, and calorie intake alone doesn't determine weight.
Personalized Nutrition: Dietary needs vary greatly between individuals based on factors like age, genetics, and cultural background.
Social Aspect of Eating: Sharing meals and making eating a communal activity can have social and health benefits.
Conclusion
"100 Million Years of Food" provides a unique perspective on human nutrition by tracing our dietary history back millions of years. Stephen Le's work challenges many common beliefs about nutrition and offers a more nuanced view of what constitutes a healthy diet.
Le's key message is that there's no universal "perfect" diet. Our nutritional needs are shaped by our evolutionary history, but they're also highly individual. What works for one person may not work for another.
The book also highlights the unintended consequences of rapid changes in our diet and lifestyle. Many modern health issues, from nutritional deficiencies to the rise in allergies, can be traced back to these changes.
Perhaps most importantly, Le reminds us that food is not just about nutrition. It's also about community, culture, and caring for one another. By understanding our food history and embracing the social aspects of eating, we can make more informed choices about our diets and potentially improve both our health and our social connections.
As we navigate the complex world of modern nutrition, Le's insights from "100 Million Years of Food" provide valuable food for thought. They encourage us to look beyond fad diets and one-size-fits-all nutritional advice, and instead consider our individual needs, our evolutionary history, and the broader context of our eating habits.
Practical Advice from the Book
Consider adding insects to your diet: While we can't survive on insects alone, incorporating them into our diet could be beneficial both nutritionally and environmentally.
Be cautious with fruit consumption: While fruits are healthy, excessive consumption of fructose can be harmful.
Balance meat consumption: Meat can be nutritious, but excessive consumption may lead to health issues.
Be aware of dairy's effects: Milk might not be as universally beneficial as once thought, especially for those from cultures without a history of dairy consumption.
Understand the potential dangers in plants: Many plants contain substances that can be harmful in large quantities. Variety and moderation are key.
Don't obsess over calories: Focus on the quality and variety of your food rather than just calorie counts.
Embrace slight overweight: Being a little overweight might actually be healthier than being at the lower end of the "normal" weight range.
Personalize your diet: Consider your age, heritage, and individual physiology when making dietary choices.
Make eating social: Try to share more meals with others to reap the social and potential health benefits of communal eating.
Consider lifestyle changes: The author suggests that selling your car and opting for more active forms of transportation could significantly improve your health.
By following these insights from "100 Million Years of Food," we can make more informed decisions about our diets and potentially improve our overall health and well-being. Remember, the key is to understand your individual needs and to view food not just as fuel, but as an important part of our social and cultural lives.