How Your Fat Tissue's Biochemicals Control Your Energy Levels

The team performed an opposite experiment in which mice were triggered to produce higher than normal levels of NAMPT in fat tissue. These mice were much more physically active, especially after fasting, compared to normal control mice. Researchers also found that physical activity in mice with low levels of NAMPT in fat tissue can be improved with NMN injection (NMN — nicotinamide mononucleotide, an enzymatic product of NAMPT). 

According to researchers, the "NAMPT signal from fat tissue may serve as a survival mechanism", and "therapy with NMN might be a possible treatment for diseases and conditions associated with aging".

Slightly Overweight People Have A Lower Mortality Rate

One big study conducted in United States and published in the Journal of the American Medical Association investigated the relative risks of mortality associated with different BMI ranges. In this study, the obesity category (BMI > 30) was associated with 111,909 excess deaths while the underweight category (BMI <18.5)  was associated with 33,746 excess deaths. 

Being overweight (BMI 25-30) was not associated with any increased mortality. Both underweight and obesity BMI values, particularly higher levels of obesity, were associated with increased mortality relative to the mortality rate of people in the normal weight category. Because of improvements in public health and medical care, the impact of obesity on mortality may have decreased over time.

Being Overweight Reduces The Risk Of Dementia

A recent cohort study suggests that overweight people are less likely to develop dementia. Researchers analyzed the medical records of nearly two million people (aged 40 years and above) in whom BMI was recorded between 1992 and 2007. Results showed that underweight people (BMI <20) had a 34 percent higher risk of dementia, compared with normal weight people. The incidence of dementia continued to fall for every increasing BMI category. 

Overweight people with a BMI of 25 to 29 had an 18 percent lower risk of dementia, and very obese people (BMI >40) had a 29 percent lower dementia risk than people of a normal body weight. Being underweight in middle and old age carries an increased risk of dementia over two decades. Results contradict the commonly accepted theory that obesity in middle age might increase the risk of dementia in old age. However, these findings need further investigation.

Slightly Overweight People Are More Resilient

There are also statistical findings which show that those who are overweight or moderately obese better tolerate various health problems. For instance, diabetes patients with normal weight are twice as likely to die compared to those who are overweight or obese. Heavier dialysis patients have a lower chance of dying than those who are of normal weight or underweight. Mild to moderate obesity poses no additional mortality risks to those already suffering from heart disease, and obesity can help people with certain cancers to live longer. The explanation for that may be that not all fat cells are equal and might have different characteristics. 

For example, belly fat tissue can release fatty acids and inflammatory compounds into the bloodstream leading to a higher LDL — bad cholesterol, blood glucose and blood pressure.

READ Can You Be Healthy And Obese?

There is no doubt that becoming heavier and heavier must, at some point, damage health and reduce life expectancy. The benefits mentioned above sound good, but they are associated only with being slightly overweight, not obese. Being too heavy is hardly ever very healthy.