Obesity has gone from rarity to an epidemic
In our grandparents’ times, obesity was a rare occurrence. This has dramatically changed over the past few decades. According to the World Health Organization, obesity has almost tripled since 1975.1 Today, more than one-eighth of the world's population is living with obesity, and nearly 3 billion people are living with either overweight or obesity.2 While this was once more prevalent in high-income countries, it is now common in most parts of the world, with obesity rates rising rapidly in low- and middle-income countries.3 Currently, in most countries, a larger number of people are affected by obesity than underweight.4 There is also an alarming rise in obesity among children. It has become a global epidemic.
Importance of obesity for our health
Obesity is one of the major risk factors for many chronic and infectious diseases, as well as cancers. Therefore, we should adopt healthy nutrition and lifestyle choices that reduce obesity, whether or not we take GLP1 drugs.
The real causes of obesity
While genetics plays a minor role, obesity is mostly due to these major factors:
Depletion of the fully functional gut microbiome
Not personalizing food choices based on each person’s biology
Overconsumption of ultra-processed foods, saturated fats, easily digestible carbohydrates, antibiotics, preservatives, and other additives
Lack of exercise
A fully functional gut microbiome and why it’s being depleted
Our gut is home to trillions of microorganisms and more than a thousand different types (species), such as bacteria, fungi, viruses, etc. These microbes encode millions of genes that can perform thousands of biochemical functions, which are the key to our health. Think of these microbes as little chemical factories that process a portion of our food and create a flood of chemicals that maintain our health or cause disease. This chemical output is determined by a combination of the gut microbes and the foods we consume. A very rich and diverse microbiome, when combined with the right food choices, produces chemicals that support our physical, mental, cognitive, and immune health. Sadly, some people have lost important members of their microbiome due to overuse of antibiotics, consumption of preservatives and other food additives, and living a sterile lifestyle.
Each person’s microbiome can produce healthy and/or disease-causing chemicals
Our microbiome mostly feeds on our food and either supports our health or potentially causes a disease. Here are some examples:
Our gut microbes can produce butyrate, a short-chain fatty acid that supports intestinal health and controls many of our physiological functions. For example, butyrate literally feeds the human cells that line the intestines, keeping them healthy, functional, and flexible. Butyrate will also signal the immune system to remember a pathogen during an infection, which will minimize or prevent future infections by the same pathogen.5
Specific gut microbes, such as Bacteroides and Veillonella, can produce vitamin K2. This vitamin is required for cardiovascular, kidney, and bone health. Many other vitamins can also be produced by the gut microbiome.6
Oral microbes play an important role in maintaining our blood pressure, especially as we get older. They do this by converting nutritional nitrates into nitrites, which end up in the stomach, where they get converted into nitric oxide (NO). NO maintains a normal (healthy) blood pressure, and reduction in NO can lead to high blood pressure, which is a risk factor for cardiovascular and kidney diseases. Therefore, it is important to not destroy the oral microbiome, especially with mouthwashes.
Many gut microbiome members, especially within Proteobacteria, can produce lipopolysaccharide (LPS), which is one of the most powerful pro-inflammatory chemicals. It is very important to adjust our diet so that LPS is minimally produced by our microbiome.
The link between weight gain and the gut microbiome
Recent research into the role of the gut microbiome in obesity has uncovered some fascinating links. One study exploring this link examined the gut bacteria in obese and lean mice and human volunteers. They found that changes in gut microbiota affected metabolism. The microbiome in obese mice could harvest more energy from food than their lean counterparts. They also found that this effect could be transmitted. Colonizing lean mice with microbiota from obese individuals significantly increased total body fat. This study indicates that the gut microbiome plays an important role in obesity. 7,8 It shows that changes in the gut microbiome have a significant impact on metabolic function.
Several other studies show the effects of the gut microbiome on insulin resistance, inflammation, and fat deposition in the body.9 They also show that the gut microbiome responds to weight loss.
The microbiome regulates several vital functions in the body, and alterations in the gut microbiome have significant effects on health and well-being. What alters the gut microbiome? Dietary composition and caloric intake seem to quickly affect gut microbial function. Antibiotic use has been shown to decrease gut bacterial communities.10 The mode of delivery during childbirth also influences the gut microbiome.
Other factors that contribute to obesity
Exercise not only burns calories but also increases sensitivity to insulin and maintains metabolic health. Everyone should exercise to some degree, at least three times a week for 30 minutes. If possible, running for 3 hours a week and doing resistance training for 2 to 3 hours per week is ideal. In addition, avoiding ultra-processed foods will help reduce obesity. These foods typically have lots of calories in the form of highly available carbohydrates. They also tend to have more saturated fats, salt, preservatives, and other food additives that can negatively impact your microbiome health, as well as your own. Whenever possible, choose whole foods, whole grains, organic meats, and foods free of any additives. For example, when choosing wheat products. ensure that the first ingredient listed is whole wheat. If it is anything except that, simply do not purchase it. Whole wheat is very healthy for most people, whereas wheat (which is whole wheat that has been stripped of most of its nutrients) is unhealthy for most people.
What this means for you
Avoiding ultra-processed foods and choosing foods that are healthy for you, based on your biology, can lead to less body weight and healthier aging. The best way to know which foods to eat and which ones to avoid is to do a functional gut microbiome test, which is only available from Viome. None of the other gut microbiome tests are functional; they can only tell you which microbes are there, but not what they are doing (or not doing) for you.
References:
World Health Organization. (2024, March 1).
World Health Organization. Obesity and overweight. World Health Organization. (2023, March 4). Obesity and overweight. World Health Organization.
World Obesity Federation. World obesity atlas 2023. (2023). World obesity atlas 2023. World Obesity Federation.
Turnbaugh PJ, Ley RE, Mahowald MA, Magrini V, Mardis ER, Gordon JI. Nature 444, 1027-1031
Bachem, A., Makhlouf, C., Binger, K. J., de Souza, D. P., Tull, D., Hochheiser, K., Whitney, P. G., Fernandez-Ruiz, D., Dähling, S., Kastenmüller, W., Jönsson, J., Gressier, E., Lew, A. M., Perdomo, C., Kupz, A., Figgett, W., Mackay, F., Oleshansky, M., Russ, B. E., Parish, I. A., & Bedoui, S. (2019). Immunity, 51(2), 285-297.e5
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