Obesity is becoming a growing concern, particularly in the United States, as the number of people with obesity continues to increase and more is learned about the negative health effects of obesity. Severe obesity, in which a person is 100 pounds or more over ideal body weight, in particular poses significant risks for severe health problems. Accordingly, a great deal of attention is being focused on treating obese patients.
Surgical procedures to treat severe obesity have included various forms of gastric and intestinal bypasses (stomach stapling), biliopancreatic diversion, adjustable gastric banding, vertical banded gastroplasty, gastric plications, and sleeve gastrectomies (removal of all or a portion of the stomach). Such surgical procedures have increasingly been performed laparoscopically. Reduced postoperative recovery time, markedly decreased post-operative pain and wound infection, and improved cosmetic outcome are well established benefits of laparoscopic surgery, derived mainly from the ability of laparoscopic surgeons to perform an operation utilizing smaller incisions of the body cavity wall. However, such surgical procedures risk a variety of complications during surgery, pose undesirable post-operative consequences such as pain and cosmetic scarring, and often require lengthy periods of patient recovery. Patients with obesity thus rarely seek or accept surgical intervention, with only about 1% of patients with obesity being surgically treated for this disorder. Furthermore, even if successfully performed and initial weight loss occurs, surgical intervention to treat obesity may not result in lasting weight loss, thereby indicating a patient's need for additional, different obesity treatment.
Nonsurgical procedures for treating obesity have also been developed. However, effective therapies for increasing energy expenditure and/or altering a patient's metabolism, e.g., a basal metabolic rate, leading to improvements in metabolic outcomes, e.g., weight loss, have focused on pharmaceutical approaches, which have various technical and physiological limitations.
It has been recognized in, for example, U.S. Pat. No. 6,645,229 filed Dec. 20, 2000 and entitled “Slimming Device,” that brown adipose tissue (BAT) plays a role in the regulation of energy expenditure and that stimulating BAT can result in patient slimming. BAT activation is regulated by the sympathetic nervous system and other physiological, e.g., hormonal and metabolic, influences. When activated, BAT removes free fatty acids (FFA) and oxygen from the blood supply for the generation of heat. The oxidative phosphorylation cycle that occurs in the mitochondria of activated BAT is shown in FIGS. 1 and 2.
Accordingly, there is a need for improved methods and devices for treating obesity and in particular for activating BAT.