From One End of the Spectrum...
Plenty of problems can crop up for overweight and obese individuals. High levels of body fat leave you more vulnerable to a laundry list of serious health conditions like coronary heart disease, diabetes, high blood pressure, liver disease, gallbladder disease and even some types of cancer. You're also more likely to have sleep apnea, which will interfere with proper rest. And obese women are more likely than those of a normal weight to have fertility problems and abnormal menstruation.
But as researchers have discovered, being overweight is not always a heath risk in and of itself. In a European study, even obese subjects were no more likely to die of heart disease or cancer than people of a normal weight if they were "metabolically fit," meaning they didn't suffer from insulin resistance, high cholesterol, high triglycerides or high blood pressure. Being overweight does increase the risk of these conditions, but if you're otherwise healthy, extra padding won't make you more likely to get sick. Interestingly, nearly half of the overweight people in the study were classified as metabolically fit.
...To the Other
Many people don't know this, but skinny people may also be more likely to get diabetes than normal-sized folks. In a 2011 study, researchers found that thinner people might carry more fat around the heart and liver as opposed to their thighs, increasing their risk. Plus, skinny people may assume they're healthy enough to live on fast food and avoid doctor visits, which can up the risk of high cholesterol and other health problems.
Underweight people may also have reduced immune function, fertility problems and increased risk of anemia. Osteoporosis, a condition in which weak, brittle bones develop from demineralization, is also far more common in thin people than heavier folks.
So What's the Lesson?
The lesson here is to strive for a healthy weight if you're too heavy or too lean. And in the end, your lifestyle choices, rather than the number on the scale, may prove most important.
Indeed, the key to a healthy life may lie in food choices and regular exercise, both of which can help stave off the chronic conditions that can plague people of any weight.
Aim for a diet of whole, unprocessed foods in a variety of colors rather than packaged or restaurant fare. Also get 150 to 300 minutes per week of cardio exercise like jogging or cycling, as well as two to three weight-training sessions (which may include home exercises like crunches and leg lifts).
Most importantly, check your health progress with a doctor, who can help monitor your weight and identify any potential medical threats.
Nina Kate is a certified fitness nutrition specialist through the National Academy of Sports Medicine (NASM). She also studied journalism at the University of California, Los Angeles (UCLA), and has contributed to numerous major publications as a freelance writer. Nina thrives on sharing nutrition and fitness knowledge to help readers lead healthy, active lives. Visit her wellness blog at BodyFlourish.com.