Being Overweight Reduces Immune Function
That "belly budge," and those "thunder thighs" are not only unsightly in appearance, they are also very bad for your health. Body fat is incredibly inflammatory, and it's that high level of inflammation that leads to infections like a cold or the flu as well as conditions like heart disease, diabetes and cancer. Being overweight or obese can lead to a weakened immune system.
Generally, an overweight person has a body mass index (BMI) of 25 or more and an obese person has a BMI of 30 or more. However, the BMI is not always a reliable measurement of whether a person is overweight or obese. For instance, athletes who are healthy sometimes have BMIs above 25.
Having too much fat on your body negatively impacts your body's ability to fight disease because body fat can inhibit the ability of white blood cells to multiply, produce antibodies, and prevent inflammation.
A study conducted by new University of North Carolina at Chapel Hill School of Medicine on laboratory mice shows that obesity reduces the body's ability to turn on elements of its immune systems needed for controlling influenza infection.