World's No.1 Exercise Professor: Our Comfortable Lives Are Causing Cancer & The Truth About Running!

Intro (00:00:00)

• The vast majority of chronic diseases in the Western world are mismatches, such as obesity, heart disease, and many cancers.
• These diseases are caused by our modern lifestyle, which is very different from the environment our bodies evolved in.
• Two actionable things to reduce the risk of these diseases are to avoid sitting for long periods and to subscribe to the channel.

What do you do, and why do you do it? (00:02:15)

• Daniel Lieberman is a professor of human evolutionary biology at Harvard University.
• He studies how and why humans are the way they are, and how that is relevant to health and disease.
• His particular specialty is the evolution of human physical activity.

Are we actually a good species? (00:03:24)

• Humans are not as fragile and weak as we think.
• We are impressive athletes, capable of outrunning most animals over long distances, throwing, and kicking.
• We are also the ultimate omnivores, able to eat a wide variety of foods.

Do our ancestors hold the answer to all our health needs? (00:05:26)

• It is not true that hunter-gatherers are role models in every respect.
• They have some health advantages over modern humans, but they also have problems such as violence and warfare.
• Natural selection cares only about reproductive success, not happiness or health.
• We evolved to eat foods that would increase our reproductive success, not necessarily foods that are healthy for us.

Have we evolved to eat meat? (00:07:47)

• Humans have been eating meat for at least 2.5 million years.
• Meat played an important role in our evolutionary history.
• However, it is possible to be a healthy human being without eating meat.
• Humans are the ultimate omnivores, able to eat a wide variety of foods.

How did we learn to hunt and gather? (00:10:48)

• Humans evolved from ape-like ancestors around 7 million years ago and became bipedal.
• As bipeds, early humans were slower than chimpanzees and likely poor hunters.
• Stone tools and evidence of butchered animals suggest hunting became part of the human repertoire between 3 and 2 million years ago.
• Hunting and gathering, along with tool making and extractive foraging, became the hunter-gatherer way of life.
• The shift to hunting and gathering coincided with significant changes in human anatomy, including the development of a more human-like body and an external nose.
• The external nose is thought to have evolved as a humidifier to regulate airflow and moisture in the respiratory system.

Have we evolved to breathe wrong? (00:17:18)

• The idea that mouth breathing during running is harmful is not supported by evidence.
• Humans evolved to breathe out of their mouths when running to dump excess heat generated during intense activity.
• Elite runners do not breathe out through their noses when running.
• Claims that nasal breathing can prevent a wide range of diseases lack sufficient scientific evidence.
• Sleep apnea, often caused by various factors including obesity and deviated septum, should be addressed by treating the underlying cause rather than relying solely on nasal strips.

Why do we sweat? (00:19:43)

• Sweating is a unique human adaptation that evolved from our hunter-gatherer ancestors.
• Unlike most animals that cool down by panting, humans have sweat glands that allow for efficient evaporation of moisture from the skin.
• This ability to dump heat effectively was crucial for our ancestors in the heat of the day when hunting.
• It's possible that sweating evolved before hunting as a means of escaping predators during the hottest part of the day.

When did our brains get so big? (00:24:38)

• The significant increase in brain size in humans occurred around the time we started hunting and gathering.
• Hunting and gathering provided more energy, reducing the constraints on brain size and allowing for selection of individuals with larger brains.
• A larger brain requires more energy, which is why humans have a higher proportion of body fat compared to other animals.
• Body fat serves as an energy reserve to support the brain's constant energy demands, especially during infancy when brain growth is rapid.
• The relatively high level of body fat and predisposition to store fat are fundamental adaptations for human survival, reproduction, and brain function.

Why do we struggle to diet? (00:30:10)

• Dieting is hard because our bodies evolved to store fat, not to lose it.
• When we diet, our bodies go into starvation mode, which causes cortisol levels to rise.
• Cortisol makes us hungry, stores fat in visceral deposits, and turns down our immune system.
• Excess fat causes inflammation, which is linked to many diseases.
• Stress also elevates cortisol levels and can lead to weight gain and fertility problems.

Modern-day mismatched diseases (00:38:46)

• Most diseases today are mismatches, meaning they are conditions for which our bodies did not evolve.
• Mismatches are caused by changes in our modern world, such as diet, physical activity, and stress.
• Heart disease, cancer, and diabetes are all examples of mismatched diseases.
• Mismatched diseases are not inevitable and can be prevented by adopting a healthy lifestyle.

Why did you write a book about food? (00:42:56)

• People today have incredible choices for food, but this can lead to poor choices.
• The author aims to help people understand the complexities of food choices and their consequences.
• There are no perfect answers, and oversimplified diets are not the solution.

Has our culture moved too fast? (00:45:17)

• Cultural evolution is rapid and transformative, leading to a mismatch between our biology and our environment.
• This mismatch has heightened the kinds of mismatches that we exist.

We've decided to live with diseases rather than prevent them. (00:46:30)

• We treat the symptoms of mismatch diseases rather than the causes.
• This enables the diseases to remain prevalent and, in some cases, get worse.
• Treating symptoms is necessary, but it would be better to prevent diseases in the first place.

The modern foods we eat have affected the way we look. (00:50:28)

• The way we chew impacts the shape of our jaws.
• Modern foods have led to smaller jaws and malocclusions, but these can be managed.
• Eating a lot of sugar and saturated fat, and being physically inactive can lead to heart disease, stiffening of blood vessels, and hypertension.

Is cancer a consequence of our modern society? (00:53:17)

• Cancer is not completely a mismatch disease.
• Cancer is a disease of evolution going wrong due to mutations.
• Cancer rates are higher in high-energy environments.
• Physical inactivity, high insulin levels, and exposure to carcinogens can increase cancer risk.
• Higher levels of estrogen and progesterone due to hormonal imbalances can increase breast cancer risk.
• Cancer rates are higher in developed countries with higher GDP.
• Hunter-gatherer women likely had lower cancer rates due to lower energy intake and fewer menstrual cycles.
• Birth control and smaller families may have elevated breast cancer rates due to increased menstrual cycles.

How our bodies store energy (00:58:49)

• Fat is a vital molecule that stores a large amount of energy.
• Fatty acids are stored as triglycerides in adipocytes, which are specialized fat-storing cells.
• Insulin helps transport triglycerides into fat cells for storage.
• Humans evolved to have a relatively high level of body fat for energy storage.
• Excess fat storage, especially ectopic fat, can lead to health problems such as fatty liver, kidney problems, heart problems, and inflammation.
• Chronic inflammation caused by overfilled fat cells can contribute to various diseases, including cardiovascular disease, Alzheimer's, and diabetes.
• The keto diet and fasting can help reduce excess body fat and improve overall health.

The keto diet and fasting (01:05:38)

• Fasting is when you go into negative energy balance.
• Intermittent fasting might be an easy way to get some of the benefits of exercise without exercising.
• Keto diets involve avoiding carbohydrates and relying on Ketone bodies for energy.
• Keto diets can lead to rapid short-term weight loss but are not very effective as a long-term weight loss strategy.

Are we too comfortable as a society? (01:09:59)

• Comfort is not necessarily good for us.
• Kids need to run around and get physical activity to build a healthy skeletal system and for other benefits.
• There is evidence that kids are getting physically weaker and less fit.
• Rates of osteoporosis are rising due to lack of physical activity.
• Exercise helps prevent bone loss by suppressing cells that cause bones to be resorbed.
• Loading bones causes them to respond and grow stronger.
• People who eat harder food tend to have larger jaws.
• Malocclusion is a consequence of jaws not having enough room for teeth.

Puberty has changed, and we’re going into it earlier than ever before. (01:15:14)

• The age at which women go through puberty has decreased significantly in the past 200 years.
• This is due to increased energy availability.
• Girls in rural areas of Kenya go through menarche about 2 years later than girls in urban areas due to differences in energy availability.
• Natural selection favors individuals who take in energy and use it to reproduce.

The dangers of sitting down all day like we do. (01:16:52)

• Sitting for long periods can increase the risk of disease, especially when combined with a sedentary lifestyle outside of work.
• Getting up and moving around frequently, even for short periods, can help mitigate the negative effects of sitting.
• Weak back muscles can contribute to back pain.
• Strong back muscles help prevent back pain.

What should people take away most from this conversation? (01:20:23)

• Understanding why we get particular kinds of mismatches helps us make decisions about how to use our bodies, what to eat, and how to be physically active.
• We need to be aware of the vicious cycle of treating the symptoms of mismatch diseases, which can worsen the underlying problems.
• Processed foods, lack of physical activity, and psychosocial stress contribute to mismatch diseases.
• Hunter-gatherers also get sick, but we can learn from their evolutionary history to make better decisions about our health.

The products we put on our bodies, are they toxic? (01:24:31)

• Be skeptical of cosmetic products and their claims.
• Most products likely have little benefit or unintended consequences.
• Killing bacteria with mouthwash may have short-term benefits but could harm the oral microbiome in the long term.
• Sanitizing our hands and living in highly sanitized environments can lead to allergies and autoimmune diseases due to an unchallenged immune system.
• Ultra-sterile environments may prevent infectious diseases but can also have costs, potentially increasing the risk of autoimmune diseases.