Obesity is a chronic multifactorial disease that is associated with increased risks of several other diseases, which include type 2 diabetes (T2D), cardiovascular disease, certain cancers, sleep apnea, subfertility, and mortality. Data from the literature predict that being overweight reduces life expectancy by 2.7 years in certain locations. Because of this, weight management interventions and their consequent reduction are associated with several health benefits.
According to the World Health Organization (WHO) “overweight” and “obesity” are defined as BMI of 25 kg/m2 or more and 30 kg/m2 or more, respectively. In which, in the world population almost four in ten adults (39%) are overweight and more than one in ten (13%) have obesity. As mentioned, overweight and obesity are responsible for a substantial burden of disease and are associated with considerable direct costs, e.g., health expenses, and indirect costs, e.g., lost productivity. It is estimated that health expenditures associated with overweight and obesity represent 2% to 8% of total health expenditures.
A few years ago, 5% of deaths worldwide have been attributed to obesity. Given this, the literature shows that modest weight loss ranging from 5% to 10% is considered clinically important, since it reduces cardiometabolic risk factors and improves obesity-related comorbidities in overweight or obese patients. On the other hand, the Large weight loss, when one has a reduction of more than 10%, may be necessary to achieve improvements in certain weight-related complications, such as sleep apnea, or for most patients with T2DM.
In this sense, it is important to highlight that the benefits of great weight loss have been observed in patients with a variety of complications related to overweight and obesity, including T2DM, prediabetes, metabolic syndrome, osteoarthritis of the knee, and subfertility. It is noteworthy that the great weight losses were achieved through bariatric surgery, lifestyle modifications or pharmacotherapy.
Remission of Type 2 Diabetes and Obesity
Studies show that after bariatric surgery, adults with obesity achieve an average weight loss of 20% to 35% and thus have reductions in fasting glucose, insulin and incidence of T2DM in 2 to 3 years. For example, a systematic review and meta-analysis showed that, after laparoscopic adjustable gastric banding and revisional bariatric surgery, almost half of the patients, or 46.5%, had diabetes remission.
In addition, patients who use lifestyle measures for weight management generally achieved lower average weight loss than those undergoing bariatric surgery, with modest improvements in glucose metabolism.
On the other hand, pharmacotherapy also showed beneficial results related to weight loss and remission of type 2 diabetes. In other words, the use of phentermine/topiramate 15/92 mg once daily was associated with an average weight loss of 10.5% after 2 years. As a result, among patients who had T2DM at baseline, after treatment with phentermine/topiramate 15/92 mg, changes in fasting blood glucose, insulin and glycated hemoglobin levels were observed.
Also, subcutaneous semaglutide (2.4 mg) once weekly was associated with an average weight loss of 14.9% after 68 weeks. As a result, improvements in fasting glucose and glycated hemoglobin were observed in the control group, and patients with prediabetes at baseline had reverted to normoglycemia at week 68.
Obesity and Risk for Cardiovascular Disease
Significant weight loss achieved through surgery was associated with long-term improvements in blood pressure and lipid profiles. In other words, an improvement in systolic blood pressure, diastolic blood pressure, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and triglyceride levels was observed in the group undergoing gastric bypass surgery compared with controls without surgery for up to 12 years. In some cases, in addition to improvement, improvement in the resolution of comorbidities such as hypertension and dyslipidemia was reported at bariatric surgery.
Although the weight loss observed in bariatric surgery apparently has greater effects on cardiovascular risk factors, benefits related to the large weight loss after lifestyle modification. After individual sessions of behavioral education and dietary counseling, a significant reduction in triglyceride and free fatty acid concentrations was observed from the beginning of the intervention.
Pharmacologically, the use of phentermine/topiramate 15/92 mg once daily improved cholesterol and triglyceride levels compared with placebo in overweight or obese patients. As well, semaglutide 2.4 mg once a week improved levels of cholesterol, triglycerides, free fatty acids, and blood pressure compared to placebo in the same patients.
Obesity and Osteoarthritis
The literature shows that in patients with overweight or obesity and osteoarthritis of the knee the average weight loss of 10% or more, obtained through diet and/or exercise, led to less overload in the knee joint, less systemic inflammation and reduced knee pain. For example, in a study of sedentary elderly people with overweight or obesity and osteoarthritis of the knee, the greatest benefits were observed among patients with weight loss greater than 10%.
Obesity, Fertility and Pregnancy
After gastric bypass surgery (RYGB) in patients with obesity and a consequent significant weight loss, improvements in sex hormones and sexual function were observed. In other words, in men with severe obesity, increased BMI was associated with lower testosterone levels and reduced quality of sex life scores, both of which improved among those who lost weight through RYGB. On the other hand, in women, bariatric surgery was associated with improvements in the duration and regularity of the menstrual cycle, conception rates and pregnancy rates.
Regarding lifestyle change in women with severe obesity and anovulatory subfertility, intensive intervention for weight loss based on a very low-energy diet was associated with 13% weight loss and improved metabolic and ovulatory outcomes.
It is worth noting that there are differences in weight loss according to the type of intervention used, although weight loss has important benefits in overweight or obese people, regardless of the approach.
In overweight or obese people, weight loss of 10% or more has important benefits, regardless of the weight loss approach. Thus, in clinical practice it is suggested that weight loss of 10% or more should be aimed at treatment when weight loss less than this does not result in sufficient beneficial effects for health.
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10% weight loss
: Tahrani AA, Morton J. Benefits of weight loss of 10% or more in patients with overweight or obesity: A review. Obesity (Silver Spring). 2022;30(4):802-840. doi:10.1002/oby.23371