What is the optimal BMI for Good Health? How Your Weight Affects Disease Risk

Find Your Optimal BMI and Reduce Health Risks with Simple Steps

Did you know that even a small weight gain over time can increase the risk of serious diseases such as diabetes, cardiovascular disease, and cancer? Research shows that the ideal BMI for the longest lifespan is between 20 and 22 and that even small lifestyle adjustments can lead to significant health benefits.

Learn how your weight affects your health—and discover simple steps to optimize your well-being. These effective measures have nothing to do with calorie counting.

What Does Research Say About Weight and Health?

We know that overweight (BMI > 25) and obesity (BMI > 30) can increase the risk of chronic diseases, but did you know that nearly 40% of the four million annual deaths linked to excess body fat occur among overweight individuals—not those classified as obese?

Two major Harvard studies show that a weight gain of just 5 kg (11 lbs) in adolescents and young adults can increase the risk of diabetes, cardiovascular disease, and cancer. On the positive side, these studies also indicate that even moderate weight loss can offer significant health benefits and lower the risk of these diseases.

What Is the Optimal BMI?

Body Mass Index (BMI) is often used to assess weight relative to height. BMI is calculated by dividing a person's weight in kilograms by their height in meters squared (kg/m²). At the population level, BMI is a useful tool for evaluating weight trends and linking weight to health risks.

However, BMI alone can overestimate body fat in highly trained individuals with significant muscle mass since muscles weigh more than fat. As a result, BMI can fall into the overweight category (≥25) without indicating excess body fat. Therefore, individual BMI assessments should be supplemented with other measurements such as waist-to-hip ratio, body fat percentage, and muscle mass for a more precise evaluation of body composition.

In Norway, the majority of the population is overweight or obese, but authorities seem to downplay the issue of excess weight. The Norwegian Institute of Public Health (FHI) emphasizes that primarily obesity (BMI ≥ 30 kg/m²) is associated with increased health risks, as obesity is linked to various diseases, including cardiovascular disease, diabetes, and other chronic conditions.

Large population studies from the U.S. and worldwide indicate that a BMI between 20 and 25 is associated with better health and longer life. The most comprehensive studies with the longest follow-up periods suggest that the optimal BMI for younger and middle-aged adults (<65 years) is between 20 and 22. However, after age 65, being slightly heavier may be beneficial. In older adults, low weight can be a challenge, and in those over 65, the lowest mortality rates are found at a slightly higher BMI than in younger adults.

For someone who is 168 cm (5'6") tall, this corresponds to a weight between 56 and 62 kg (123–137 lbs). Even within the "normal" BMI range (18.5 to 24.9), research shows that the risk of chronic diseases increases as BMI rises. In fact, a BMI of 24.5 can double the risk of cardiovascular disease compared to a BMI of 18.5.

Can You Be "Overweight but Healthy"?

You may have heard of the term "fat but fit," meaning overweight but still metabolically healthy. However, studies of over 600 centenarians showed that only 1% of women and none of the men were obese in their younger years.

There are a few individuals classified as having "metabolically healthy obesity," meaning they do not develop high blood pressure, diabetes, or poor cholesterol levels. However, studies with long follow-up periods show that even these individuals have an increased risk of diabetes, fatty liver disease, and cardiovascular disease over time. So, even if you are lucky enough to avoid immediate health problems today, they may emerge in the future.

The Path to a Healthy Weight – Small Changes, Big Impact

The good news is that you don't need a drastic lifestyle overhaul to reap health benefits. Small changes in diet, activity, and stress management can lead to significant results.

Fill Your Plate with Gut-Friendly Foods

Cook with whole ingredients. Eat more vegetables, include healthy fats, and consume fermented, cultured, or aged foods to support a healthy gut microbiome. The GØT app offers a range of #gutfriendly recipes to help you nourish your gut. Get a preview and try some of the GØT recipes here.

Move More Throughout the Day

Small efforts like taking the stairs, biking to work, or going for a short walk after meals can make a difference. Try a sensory walk, simple yoga exercises, or guided outdoor meditation to increase movement and reduce stress. In the GØT app we have a large selection of classes under "Activity" - from hiit workout, yoga, walking meditation, to couple's workout - something for everyone!

Prioritize Sleep and Reduce Stress

Poor sleep quality and chronic stress can lead to weight gain, even if you eat well and exercise regularly. That’s why the GØT app focuses on all four pillars of gut health. It guides you toward better digestion, increased metabolism, and healthy weight loss if needed—acting as your personal "gut trainer."

In the GØT app, you’ll find classes under categories such as Sleep, De-Stress, and Self-care – read more about the app here.

Conclusion

There is no such thing as "healthy obesity." Even a small weight gain over time can impact health, but that doesn’t mean you need a "perfect" BMI to be healthy. Fortunately, even moderate weight loss can provide significant health benefits—and it’s not about dieting but rather giving your body the nutrition, movement, and rest it needs to function optimally.

💙 Take care of yourself—strengthen your gut health. Your body will thank you!

References:

• GBD 2015 Obesity Collaborators. "Health effects of overweight and obesity in 195 countries over 25 years." New England journal of medicine 377.1 (2017): 13-27.

• Zheng, Yan, et al. "Associations of weight gain from early to middle adulthood with major health outcomes later in life." Jama318.3 (2017): 255-269.

• Aune, Dagfinn, et al. "BMI and all cause mortality: systematic review and non-linear dose-response meta-analysis of 230 cohort studies with 3.74 million deaths among 30.3 million participants." bmj 353 (2016).

• Fontana, Luigi, and Frank B. Hu. "Optimal body weight for health and longevity: bridging basic, clinical, and population research." Aging cell 13.3 (2014): 391-400.

• Saguy, Abigail C., and Kevin W. Riley. "Weighing both sides: Morality, mortality, and framing contests over obesity." Journal of health politics, policy and law 30.5 (2005): 869-923.

• Santos-Lozano, Alejandro, et al. "Implications of obesity in exceptional longevity." Annals of Translational Medicine 4.20 (2016).

• Brown, R. E., and J. L. Kuk. "Consequences of obesity and weight loss: a devil's advocate position." obesity reviews 16.1 (2015): 77-87.

• Kramer, Caroline K., Bernard Zinman, and Ravi Retnakaran. "Are metabolically healthy overweight and obesity benign conditions? A systematic review and meta-analysis." Annals of internal medicine 159.11 (2013): 758-769.

• Appleton, Sarah L., et al. "Diabetes and cardiovascular disease outcomes in the metabolically healthy obese phenotype: a cohort study." Diabetes care 36.8 (2013): 2388-2394.

• Bell, Joshua A., Mika Kivimaki, and Mark Hamer. "Metabolically healthy obesity and risk of incident type 2 diabetes: a meta‐analysis of prospective cohort studies." Obesity reviews 15.6 (2014): 504-515.

•  Chang, Yoosoo, et al. "Metabolically healthy obesity and the development of nonalcoholic fatty liver disease." Official journal of the American College of Gastroenterology| ACG 111.8 (2016): 1133-1140.

• Kramer, Caroline K., Bernard Zinman, and Ravi Retnakaran. "Are metabolically healthy overweight and obesity benign conditions? A systematic review and meta-analysis." Annals of internal medicine 159.11 (2013): 758-769.

• Hill, James O., and Holly R. Wyatt. "The myth of healthy obesity." Annals of internal medicine 159.11 (2013): 789-790.