Obesity is a growing concern in all age groups and the prevalence is rapidly increasing worldwide. A Body Mass Index (BMI) of 25 kg/m² is considered overweight and 30 kg/m² is considered obese. People can have a normal body mass index and still be obese. A person is obese if his/her fat percentage is high. The cheapest, easily accessible and not-so-accurate tool to measure BMI is a person’s height and weight. 

A person is said to be normal weight obese (NWO) if his/her BMI is normal and has a higher body fat percentage. NWO is often overlooked. There are racial and ethnic variations in different population groups as far as diagnostic criteria for obesity are concerned. People are generally unaware of the risks associated with Normal Weight Obesity (NWO) because they do not measure their visceral fat. Excessive fat percentage in a normal-weight obese person can increase the risk of type 2 diabetes, dyslipidaemia, impaired glucose tolerance, stroke and cardiovascular diseases.

Story of Body Mass Index (BMI)

The Body Mass Index was developed between 1830 and 1850 by Adolphe Quetelet. He called it the Quetelet Index. So, BMI was discovered nearly 200 years ago and is less relevant. As mentioned above BMI is still used as this is not expensive and easy to calculate.

We now have sophisticated equipment like CT scans, DEXA scans and Bioimpedance body composition analysers to measure body fat. Hence using BMI to diagnose obesity should be avoided especially in people with high risk of diabetes and cardiovascular disease.

Let us look into Alex’s story.

Alex’s story

Alex is a 25-year-old male with a BMI of 22 kg/m2. He visited his primary care physician complaining of recurring health issues despite appearing to be of normal weight. He reported feeling fatigued, experiencing frequent mood swings, and having digestive problems, including bloating and irregular bowel movements. He also mentioned an increased susceptibility to minor infections.

What is Normal Weight Obesity (NWO)?

Abnormal or excessive fat accumulation that may impair health is defined as obesity (WHO). It has become a public health problem. Body mass index is a simple parameter established by the WHO to identify overweight and obesity although it does not differentiate fat-free mass from adipose tissue and does not provide the full body composition. A person may have an excessive body fat percentage but still may fall under normal BMI, this is called Normal Weight Obesity (NWO). NWO can be defined as when a person with an increased body fat percentage but the BMI indicates ≤30 kg/m2. This however may vary depending on their ethnic group. 

Although Alex had no obvious medical issues, his family had a history of heart problems. His diet consisted mainly of processed foods and was deficient in essential nutrients. He frequently indulged in snacks instead of meals. His lifestyle is sedentary and engages in minimum physical activity.

Factors contributing to Normal Weight Obesity

Normal Weight Obesity (NWO) can be misleading because people with this condition may not appear overweight, but they can still be at risk for various health problems associated with excess body fat.

Some of the factors that contribute to normal weight obesity include,

    • Sedentary lifestyle

    •  Poor quality diet

    •  Lack of exercise

    •  Genetic predisposition

    Health risk of Normal Weight Obesity (NWO)

    Alex had elevated blood pressure, high triglycerides, and impaired glucose metabolism. He experienced mood swings, irritability, and chronic fatigue. He also had bloating and irregular bowel movements due to his poor dietary choices.

      • Even in people with a normal BMI, excess body fat can raise the risk of cardiovascular disease and contribute to illnesses like high blood pressure, and high cholesterol.

      • People who are normal weight and have a high body fat percentage may be at risk for metabolic syndrome and insulin resistance, both of which can result in type 2 diabetes.

      • Chronic inflammation, which is associated with several chronic diseases including cancer and autoimmune illnesses, can be brought on by excess body fat.

      • Lack of physical activity and muscle mass can contribute to decreased bone density and physical function, which may increase the risk of fractures, osteoporosis, and quality of life.

      Dietary choices for Normal Weight Obesity (NWO)

      Dietary decisions should be made for those with normal weight obesity (NWO) to decrease body fat percentage while maintaining or gaining lean muscle mass. Enhancing metabolic health and general well-being should be the main priorities.

      Points to focus on for Alex:

        • Be mindful of portion sizes to prevent overeating and promote weight loss. Use smaller plates and avoid large portions unless necessary. Aim for regular meal times to regulate your metabolism and to avoid overeating. Do not skip meals, especially breakfast.

        • Choose complex carbohydrates like whole grains and fibre-rich food like vegetables and fruits—Minimise refined carbohydrates like white bread and sugary snacks and beverages.

        • Include lean sources of protein to support muscle growth and repair. Protein sources include chicken, fish, tofu, legumes, and low-fat dairy products.

        • Include healthy fats, such as avocados, nuts, seeds, and olive oil. These fats help improve satiety and provide essential nutrients.

        • Consume plenty of high-fibre foods like fruits, vegetables, whole grains, and legumes. Fibre aids digestion, reduces bloating, and promotes feelings of fullness.

        • Stay well hydrated – Drink plenty of water throughout the day to stay hydrated. Sometimes people confuse thirst with being hungry, which results in overeating.

        • Combine a balanced diet with a regular exercise routine, including strength training, to build lean muscle mass and improve metabolism.

        Conclusion 

        The rise in obesity has led to a focus on Body Mass Index (BMI), but it may not fully capture the full spectrum of health risks. Normal Weight Obesity (NWO) is a scenario where individuals with a seemingly normal BMI exhibit higher body fat percentages, often undetected due to reliance on traditional measures. NWO can contribute to elevated health risks, including cardiovascular diseases, metabolic syndrome, insulin resistance, and chronic inflammation. Recognising NWO as a potential health concern requires a more comprehensive approach to assessment beyond BMI. Lifestyle modifications, such as dietary modification and regular exercise, can mitigate the negative impact of excess body fat on metabolic health, mood disorders, and overall well-being.

        Kripa & Priyanka,
        Clinical Dietitians, Simplyweight