Léo RamosObese adolescents may find that by losing just 8% of body weight, equal to 6-11 kilograms (kg) [1 kg=2.2 lbs.], they can undo the metabolic changes caused by obesity, keep hunger in check and reduce the risk of diabetes, hypertension and cardiovascular disease, which usually accompany it. “No need to lose 20 kg in a short period of time, which is the usual recommendation, to avoid the health problems aggravated by excess weight,” says Ana Dâmaso, a Federal University of São Paulo (Unifesp) professor and coordinator of the interdisciplinary study that led to these conclusions. Doctors, nutritionists, psychologists, physical educators and physical therapists followed 77 adolescents for one year, who ranged in age from 14 to 19 and weighed between 101 and 120 kg. They were encouraged to gradually lose weight through physical exercise and by incorporating a diet rich in fruits and vegetables and by adopting a healthier lifestyle, such as going to bed earlier and getting at least eight hours of sleep, instead of spending the night on the internet eating potato chips.
Prior studies had already linked obesity to an increased risk of type 2 diabetes, hypertension, cancer, kidney, pancreas and liver problems, as well as trouble sleeping; they also found that a loss of 5 kg cut the risk of diabetes in half. These new studies will now begin to determine the amount of weight loss—to be confirmed or revised by other studies—needed for the body to achieve a healthy balance. These advances are significant because adolescents are a group at risk for health problems: it is estimated that the number of overweight adolescents in Brazil has tripled in the last decade—rising from 4% to 13%. According to the Ministry of Health, 20% of adolescents and 48% of the population are above the recommended weight for their age and height. “The earlier we begin to work with obese adolescents and initiate lifestyle changes, the lower the burden of chronic diseases will be for adults and the lower the future costs of public health,” says Danielle Caranti, who while studying for her PhD worked with obese adolescents at a hospital for metabolic diseases in Italy. Then in 2010 she began working with adults at Unifesp in the city of Santos, São Paulo State.
Obese adults probably have to lose more weight than adolescents to reverse the metabolic changes caused by obesity. According to an ongoing study of 43 people ranging in age from 21 to 60 at Unifesp Santos, the hormone levels that control appetite and the resulting inflammation from excess weight can be up to three times above normal, which require more time and effort to return to levels considered healthy. According to Caranti, the coordinator of this research, preliminary results indicate that, in adults, the minimal reduction in body weight necessary to normalize the levels of key hormones linked to obesity appears to be around 10% to 20%; this value can only be achieved after at least one year of physical exercise and adjustments in diet and lifestyle. A recent study by a group led by Mario Saad at the State University of Campinas (Unicamp) indicates that, in mice, physical exercise, in addition to burning calories, which is widely known, helps to reduce inflammation in the neurons of the hypothalamus, the region of the brain that regulates hunger and establishes satiety (see Pesquisa FAPESP No. 173).
These studies indicate that it is important to lose weight gradually to allow the body time to reestablish its lost equilibrium, rather than trying to lose the weight all at once. “When you lose weight too quickly, abdominal fat tends to gravitate toward the liver and heart,” says Dâmaso. To avoid the euphoria of losing weight quickly and then gaining it all back, the researchers suggested that the adolescents should aim to lose around 0.5 to 1.5 kg per week––after one year of treatment, some of them had lost up to 22 kg.
Another conclusion already adopted by other research groups is that obesity should be viewed as a chronic multifactorial disease, and thus needs to be treated in a comprehensive manner. Both adolescents and adults underwent interdisciplinary therapy for weight reduction, which Professor Dâmaso became familiar with in Germany in 2002 and implemented at Unifesp two years later. In recent years, this approach has been applied and evaluated by other research groups in Paraná, Pernambuco and São Paulo, with variable durations from 3 to 12 months.
Through this strategy, physicians, physical educators, physical therapists, psychologists and nutritionists are adopting the same objectives and proposing lifestyle changes for adolescents and adults. “We need to tackle obesity on several fronts all at the same time,” says Caranti. In principle, it is easier for adolescents to lose weight, although obese adults can also change their behavior. Joana Ferreira, of the Unifesp group, found that the average daily intake of calories in a group of 49 obese adults decreased from 2,195 kilocalories (kcal) to 1,603 kcal, and binge eating decreased from 23.8% to 4.8% among the moderately obese and from 9.5% to 0% among the severely obese, after six months of treatment.
Gains are in proportion to the weight loss, according to an article published this month in the journal Clinical Endocrinology. After one year of treatment, the first of the four groups into which the adolescents were divided lost up to 5.8 kg or 3.4% of body weight. The 19 adolescents in this group showed a reduced blood level of the main appetite regulatory hormone, leptin, but it did not return to the normal of 24 nanograms per deciliter (see graph).
The results and health benefits became more apparent in the second group of 19 participants; they lost weight in the range of 5.8 to 10.9 kg, equal to 8% of body weight. The average level of leptin in this group was much higher, but fell more sharply, almost to the normal level. According to this study, the reduced level of leptin promoted weight loss and contributed to reducing the so-called subclinical inflammation that is characteristic of obesity, which increases the risk of cardiovascular disease. With an 8% reduction in body weight the levels of abdominal fat and liver fat returned to normal.
The third group of 19 participants lost 11 to 16 kg, or 12% of body weight. In addition to showing even more pronounced declines in leptin, they also significantly reduced some factors of the so-called metabolic syndrome, characterized by excess sugar and lipids in the blood and high blood pressure. Two indicators of risk for cardiovascular disease: the level of triglycerides, assessed by a blood test, and the wall thickness of the carotid artery in the neck, as measured by ultrasound, also returned to normal.
The 20 members of group 4 lost at least 16 kg, or 19% of body weight, and they benefited the most: the concentration of LDL cholesterol and blood pressure both returned to normal levels. This was the only group in which the level of adiponectin—the main hormone that inhibits inflammation, reduces the risk of heart and blood vessel problems, and helps regulate insulin action and glucose absorption—increased to normal and regularized the metabolism of the obese adolescents.
Sweat more, eat better
These gains resulted from various types of adaptations and changes in lifestyle. The adolescents participated in a weight-loss program that lasted one year and included four areas of action. The first consisted of monthly medical evaluations, including blood tests and ultrasounds.
The second involved group and individual counseling to identify and manage depression, anxiety or compulsive eating, which leads to overeating; these factors are not always considered when treating weight loss. In a study published this year in the British Journal of Medicine & Medical Research, a team from the Federal University of Pernambuco (UFPE), after interviewing 128 obese adolescents (76 girls and 52 boys), found that a lack of self-control and a lack of social support were the main barriers to weight loss.
The third front of activities included three one-hour sessions per week of aerobic exercise and weight training to promote fat burning. Because Santos did not have a specific facility for the practical activities of the research group, Caranti made her group of 40 overweight men and women run, dance and jump in an amphitheater or other area outside the university. The researchers suggested that the adolescents and adults continue to engage in regular exercise outside of the gym sessions, by taking walks, surfing, canoeing, climbing stairs or dancing.
The fourth consisted of weekly lectures by nutritionists. “Many wanted to eat better, but did not know how or what to eat,” said Deborah Masquio one of the group’s nutritionists. In one of the classes, the adolescents were blindfolded and asked to try different foods such as broccoli, carrots, melon and papaya. “Many said they didn’t like them, but neither had they ever tasted them,” she noted.
The lifestyle changes even included chewing more slowly as a way to control appetite. “Those who eat fast eat more than they actually need to maintain their weight,” Masquio said. Once a month, the nutritionists stressed the importance of varying foods in conversations with the parents of teenage boys, who in general were also overweight (only 11% were in the range of recommended weight for their height and age).
Many abandoned the treatment—of the 132 adolescents who began the one-year treatment, only 77 reached the end—because the results were slow to appear. Weight reduction and the change in body image became more evident six months after the start of the program. “The girls began to pay more attention to grooming, they put on lipstick and combed their hair more meticulously,” said Dâmaso.
With the reduction in weight, the adolescents shed clothes, which no longer fit, and saw the anxiety that made then overeat fade away. Some lost up to 25 kg, and their bodies had to readapt, for example, to relearn how to walk and climb stairs. But not everyone lost weight. In December 2011, at the final interview with the researchers, one 15-year-old adolescent apologized for not having lost weight. She felt that she had let them down. She then told them not to worry because she was now able to go shopping and not feel embarrassed, a result of the psychological support she had received during the treatment.
1. Influence of hyperleptinemia on inflammatory and atherogenic responses in obese adolescents; Grant Mechanism Regular Line of Research Project Award (2011/50414-0); Coordinator Ana Dâmaso / Unifesp – Santos; Investment R$68,026.14 (FAPESP).
2. Effects of interdisciplinary therapy on metabolic syndrome control in obese adults and their relationship to pro- and anti-inflammatory adipokines (11/51723-7); Grant Mechanism Regular Line of Research Project Award; Coordinator Danielle Arisa Caranti / Unifesp – Santos; Investment R$228,228.51.
MASQUIO, D.C.L. et al. The effect of weight loss magnitude on pro-/anti-inflammatory adipokines and carotid intima-media thickness in obese adolescents engaged in interdisciplinary weight loss therapy. Clinical Endocrinology. 79, p. 55-64. 2013.
LOFRANO-PRADO, M. C. et al. Reasons and barriers to lose weight: obese adolescents’ point of view. British Journal of Medicine & Medical Research v.3, n.3, p.474-82. 2013.
CARVALHO-FERREIRA, J. P. et al. Interdisciplinary lifestyle therapy improves binge eating symptoms and body image dissatisfaction in Brazilian obese adults. Trends in Psychiatry and Psychotherapy, v. 34, p. 223-33. 2012.