According to the World Health Organization, in 2012, more than 40 million children under the age of five were overweight or obese. In 2013, 2.1 billion people – almost 30% of the global population – were obese or overweight. Researchers at Tulane University have estimated that by 2030 the global number of overweight and obese people may reach about 3.3 billion. Obesity is quickly becoming a serious health problem worldwide, both in developed and developing countries.
Obesity and the Immune System
Scientists claim that obesity can weaken the immune system and reduce its ability to fight off infections. U.S. scientists have found that obesity can significantly weaken resistance against influenza in mice, causing the infected mice to have a significantly higher mortality rate. The finding shows that obesity is likely to have the same effects on humans. Experimental studies done by Dr. Melinda A. Beck, Associate Professor of Pediatrics at the University of North Carolina, and doctoral student Alexia Smith reveal that obesity has a profound impact on the immune system. Their research has shown that in the face of new, future strains of flu, obese people are more vulnerable than people at healthy weights. In one of their studies, 35 lab mice fed a high-sugar and high-fat diet for five months grew 37% heavier and had a 10% higher body fat percentage than 35 lab mice that were fed a regular rodent diet. The researchers then infected the two groups with a flu virus and checked their respective immune responses. They observed that the immune systems of the obese mice were weaker than the healthy mice in every aspect. In the end, 40% of the obese mice died from the flu, whereas only 4% of the lean mice died. Researchers also found that the lethality of natural killer cells in the obese mice was 50% lower than that of the lean mice. In addition, these researchers believed that the obese mice had abnormal immune responses against the flu. This suggests that obese people’s immune systems may have poor responses to the flu, especially when facing new strains, and their risk of dying from the flu is far higher.
Excessive caloric intake in our daily diets can raise blood sugar levels, thus leading to oxidative damage. Oxidative damage is mainly due to the population of reactive oxygen species in the body. Oxidative damage is associated with Alzheimer’s disease, Parkinson’s disease, and other neurodegenerative diseases.
What’s more, obese people have
- 40% higher risk of dying of heart disease
- 60-120% higher risk of dying of diabetes, kidney, or liver disease
- 10% higher risk of fatal cancer
- 20% higher risk of respiratory-related mortality
- 37% higher risk of asthma.
Eating more vegetables and fruits daily can help increase the intake of fiber and antioxidants. This not only boosts health, but also helps nourish the immune system with proper nutrition that keeps it healthy.
How Do You Know If You Are Obese?
to see if your weight is healthy, calculate your body mass index (BMI).
BMI=Weight (kg)/[Height (meters) x Height (meters)]
| Asians | Less than 18.5 | 18.5-22.9 | 23-27.4 | 27.5 and above |
| Non-Asians | Less than 18.5 | 18.5-24.9 | 25-29.9 | 30 and above |
| You Are | underweight | healthy | overweight | obese |
For example, if your weight is 70 kg and your height is 165 cm, your BMI is 25.7 (overweight).
