More and more Americans are dealing with obesity, but it may not be obvious to those who are dealing with it.
According to the United States National Health and Nutrition Examination Survey from 2017 to 2018, among Americans aged 20 and above, 42.5 percent were obese, and 31.1 percent were overweight. Together, they accounted for 73.6 percent of this population.
This means that approximately three out of four adults were overweight or obese. However, only 41 percent of U.S. adults considered themselves overweight, according to a Gallup survey from 2017 to 2021. Fifty-three percent felt their weight was normal.
The Causes of Obesity
According to conventional medicine, the main reason for obesity is that there is more energy stored in the body than the body can use. The excess energy is stored in fat cells called adipocytes, and leads to obesity.However, knowing that isn’t enough to treat obesity.
Intestinal Bacteria Imbalance
There’s now a deeper understanding of the gut microbiome and the relationship between gut bacteria and some diseases, including obesity.There are approximately over a trillion bacteria in the human body, with a total mass of about 0.2 kg (7 ounces). Most of them are in the intestines. When a person’s intestinal microbiota are imbalanced, there is potential for obesity.
Animal studies found that lab rats with imbalanced intestinal microbiota had a 20 percent increase in body weight.
A study published in Nature in 2006 found certain gut microbiomes were better at absorbing energy from the diet. Mice with “obese microbiota,” which readily absorbed energy, had more whole-body fat gain than those with “lean microbiota.”
People with obesity have a different composition of intestinal microbiota compared to healthy people. They have lower levels of Bifidobacterium, anti-inflammatory Faecalibacterium, and butyrate-producing Ruminococcaceae, all of which are “good” bacteria. At the same time, Bacillus and potentially opportunistic pathogens such as Fusobacterium and Escherichia-Shigella were higher in those with obesity.
Changes in specific intestinal microbiomes can lead to changes in enzyme and short-chain fatty acid production, which can affect insulin and glucose regulation and ultimately lead to obesity. One study published in Science in 2013 transplanted the feces of twin sisters, one obese and one not, in different mice. Under the same diet and living conditions, the mice that received the feces of the obese twin gained weight, and the mice that received feces from the other twin remained slim.
A study published in Gastroenterology in 2013 examined what happened when microbiota from lean donors were transplanted into people with metabolic syndrome. The results showed that the recipients’ insulin sensitivity increased, as well as their intestinal bacteria.
Hormonal Imbalance
Hormones play an important role in determining body weight. Some hormones are closely related to appetite. The desire for food is regulated by the neurological and hormonal signals between the intestinal tract and the central nervous system. The concentration of hormones such as glucagon-like peptide, oxyntomodulin, leptin, peptide tyrosine-tyrosine, and cholecystokinin is released into the blood after a person eats. They signal to important areas of the central nervous system how hungry the person is. How many of these hormones get released is influenced by what’s in the meal and how many calories it has.Many hormones affect body weight; below are a few examples:
Glucagon-Like Peptide
Glucagon-like peptide is produced in the intestinal tract when food enters the intestines. It stimulates the release of insulin, which lowers blood sugar levels, and inhibits glucagon, which raises blood sugar levels. This keeps a person’s blood sugar level stable, while making them feel satiated.Studies have shown that people with obesity may have problems with the signaling of glucagon-like peptides.
Cholecystokinin
Similar to glucagon-like peptides, cholecystokinin is a satiety hormone produced by the intestinal tract after a meal. Cholecystokinin can suppress hunger and increase the release of leptin. Reduced sensitivity to cholecystokinin may result in chronic overeating, which may further reduce cholecystokinin sensitivity. This forms a vicious cycle that can lead to obesity.Leptin
Leptin is a satiety hormone produced and secreted by adipose tissues, and is directly related to the amount of body fat. Leptin tells the brain that the stomach doesn’t need more food. People with obesity have higher leptin levels than those with normal body weight. This may be a cause of leptin resistance, in which the brain loses its sensitivity to leptin. Without that signal, someone with leptin resistance will keep eating, which in turn causes leptin to keep rising.Peptide Tyrosine-Tyrosine
Peptide tyrosine-tyrosine is another satiety hormone produced in the intestinal tract that can reduce appetite. The level of peptide YY secretion is proportional to the amount of fat consumed during meals. Compared to people with normal body weight, obese people secrete less peptide YY after meals, which may lead to uncontrolled overeating.In contrast to the hormones that make people stop eating, there are also hormones that stimulate appetite and make people want to eat.
Ghrelin (Growth Hormone-Releasing Acylated Peptide)
Growth hormone-releasing acylated peptide, also known as ghrelin, is an appetite-stimulating hormone. It signals to the hypothalamus in the brain that the stomach is empty and food is needed. Its level in the body rises one to two hours before a meal and decreases shortly afterward.If ghrelin is released, the person will feel hungry, and their body will reduce the amount of energy used at rest and decrease metabolism of fat tissue. People with obesity have lower levels of ghrelin, but their bodies are more sensitive to its effects, which may lead to overeating.
3 Ways to Lose Weight
Three ways to lose weight and suppress weight gain are:1. Eat Fermented Foods and Those Rich in Complex Carbohydrates
The human body lacks certain enzymes and, as a result, cannot digest some complex carbohydrates, such as fiber and resistant starch. However, these complex carbohydrates are the food for many good bacteria in the intestines.Eating foods rich in fiber and resistant starch, such as whole grains, beans, fruits, and vegetables, can stimulate the growth of these good bacteria.
Researchers have grown bifidobacteria, a beneficial bacterium, with fibers extracted from artichokes. They found that its growth rate was twice as fast as that of the same bacteria cultivated with glucose, the sugar found in blood. Several other studies have also shown that whole grains promote the growth of the good bacteria, including Bifidobacterium, Lactobacillus, and Bacteroides.
Fermented foods such as yogurt, kimchi, and sauerkraut can improve the intestinal microbiome by providing probiotics and inhibiting the growth of bad bacteria.
In addition, taking probiotics can increase the levels of hormones that tell us when we’re full. An animal study published in Diabetes Care in 2015 found that the release of glucagon-like peptides-1 and -2 increased by 76 percent and 43 percent, respectively, in subjects who took Lactobacillus reuteri SD5865 daily, compared to those taking a placebo.
2. Eat Protein-Rich Foods
Many dietary experiments have demonstrated the effects of high-protein diets on weight loss.A high-protein diet allows the body to more easily generate and release satiety hormones, while reducing ghrelin levels.
Among protein-rich foods, yogurt and milk can increase the concentration of glucagon-like peptides in the body.
Eggs produce a similar reaction. In a 2015 study published in Hormone Research in Paediatrics, 156 obese adolescents were randomly divided into two groups. One group was given eggs for breakfast, while the other was given steamed buns. Both had the same number of calories, but the results showed that those who had eggs for breakfast felt more full. As a result, they ate less at lunch and, over 3 months, lost weight.
The blood levels of peptide YY and glucagon-like peptide, both satiety hormones, increased in the adolescents who had eggs for breakfast. These elevated levels were maintained up to three hours after the meal. Among those who ate eggs, the level of peptide YY was maintained at 66 percent, compared to 18 percent in the group that ate buns. The postprandial glucagon-like peptide, which tells the brain when the stomach is full, in adolescents who ate buns, rose rapidly and then fell rapidly.
3. Exercise Regularly
Research has shown that regular exercise can adjust multiple weight-related hormone levels in the body.Insulin: Regular exercise can enhance the body’s sensitivity to insulin and reduce insulin resistance.
Leptin: In a 2018 review and meta-analysis examining the impact of exercise on leptin, researchers found that exercise lasting more than two weeks can alleviate the body’s leptin resistance and adjust the leptin level to a reasonable range.
Growth Hormone-Releasing Peptide: Experimental evidence suggests that an increase in growth hormones may reduce how much ghrelin gets released.
Glucagon-Like Peptide: In people who are overweight, intense intermittent exercise can lead to a significant, sustained reduction in appetite. Not only is the concentration of ghrelin suppressed immediately after exercise, but the level of glucagon-like peptide increases.
In addition, regular sleep, the maintenance of a proper body weight, and stress reduction can all help the body maintain its hormonal balance.
