Although I have spent the last 14 years treating obesity, it is rare indeed that I work with an individual like Chris who is able to both lose and sustain a 200-lb drop in weight for over 10 years. For him, this represents a drop of 44% of his initial body weight, significantly exceeding the expected sustained weight loss from gastric bypass surgery. Chris’s account of his change in lifestyle helps explain this dramatic result.
Because obesity is a progressive disease, the body weight tends to rise over the years. Most affected individuals will undergo various self-directed weight loss attempts. These usually consist of a change in diet and an increase in physical activity, or the proverbial “eat less, exercise more.”
Unfortunately, within 1 year individuals on average regain 50% of what was lost . In fact, current science suggests that “eat less, move more” does not in fact lead to sustained weight loss [2, 3] because the body will sense the lower weight as abnormally low and respond by increasing appetite signals  and decreasing the resting metabolic rate . These adaptations oppose sustained weight loss.
It has long been suggested that if a person loses weight and keeps it off, the risk of regain is mitigated and that the body will establish a new “set point.” However, recent evidence suggests that this is incorrect because all the reasons the person developed obesity in the first place persist, in spite of maintaining a stable lower weight, and in fact, the weight-reduced individual must be highly vigilant to prevent weight regain.
A recent study highlighted this, showing that 6 years after a dramatic weight loss, participants on the TV show “The Biggest Loser” had persisting changes in both levels of hunger hormones and in energy expenditure . Even though participants regained on average three-quarters of the lost weight, they still sustained an 11% weight loss. Maintaining this amount of loss required a significant increase in physical activity because of the opposing effects exerted by the body. In fact, after 6 years, despite weight regain, the resting metabolic rate was still suppressed by 500 kcal compared to expected.
In another study, maintenance of ≥10% reduction in body weight was met by a 20% decrease in 24-h energy expenditure, a 30% decrease in non-resting energy expenditure, and an improvement in skeletal muscle work efficiency by 20% .
An additional hurdle in maintaining weight loss is that when body weight is reduced, hormonal adaptations resist the reductions in weight . The stomach produces more ghrelin, a hormone that is a potent stimulator of hunger. The small intestine produces less glucagon-like peptide 1, peptide YY and cholecystokinin resulting in a decrease in satisfaction from food, and the reduced body fat mass results in a lower level of leptin resulting in higher levels of hunger. These changes persist for at least 1 year after weight loss. Further studies are needed to see if these changes are permanent.
What does this mean to the person who has lost weight? Whether a person has obesity or not, they will experience a higher level of hunger, a decrease in the ability to feel satisfied when eating, a decrease in energy requirements, and a decrease in the number of calories burned during the day. This is a perfect storm for energy regain. The body will restore the lost weight back to the weight it perceives as “normal.” Clinically, patients report a loss in “motivation” or “willpower” with regards to sticking with their eating and exercise plan. In reality, due to these hormonal changes, weight-reduced individuals do not experience satisfaction when they eat the same foods that used to provide satisfaction.
Unfortunately, this concept seems counter-intuitive to both patients affected by obesity and the providers who care for them. After all, if an individual is at an “abnormally high” body mass index (BMI) and they lose weight to a more “normal” BMI, at that point, shouldn’t the body protect this new, healthier weight? As it turns out, weight management is more complicated than the old ideas of “energy in, energy out.” Understanding that body weight regulation is complex and accepting that, for most individuals affected by obesity, the causes of weight gain are not mitigated by weight loss, we can start to grasp why sustained reductions in weight are so difficult.
Because of these hormonal and metabolic adaptations, we need to explore strategies for sustained weight loss beyond “eat less, move more.” In the face of a heightened appetite, decreased metabolism, and improved muscle efficiency, eating less will result in even more hunger and exercising more won’t burn the number of calories desired. In addition, trying to eat less and exercise more becomes demotivating. How much is “less”? How much is “more”? And, trying not to eat when hungry leaves people feeling drained of willpower, motivation, and energy.
This is where the idea of decreasing sedentary time becomes interesting. Most people think of their time as either sedentary or exercise. The truth of the matter is that there are a lot of potential steps between sitting and exercising (no pun intended). Instead of focusing on exercising more, we can focus on sitting less.
Excess sitting has been found to increase mortality—in one study, each 1 h of sitting daily increases overall mortality by 2% . Many individuals affected by obesity have largely sedentary jobs. Current recommendations suggest that sustaining weight loss may require 1–2 h per day of moderate physical activity . There can be many hurdles to achieving this ranging from not enough time in the day due to other obligations including work and family to physical limitations (joint osteoarthritis, low back pain, neuropathy, fatigue, etc.). This is why it is important to explore strategies to increase activity that won’t aggravate other medical problems or require extra time out of the day.
If instead of exercise we can find time during the work day to not sit, we can make a significant intervention, not only enhancing the individual’s odds at successfully maintaining weight loss, but also perhaps decreasing the risks associated with excess sitting.
This concept has been termed non-exercise activity thermogenesis or “NEAT” by Dr. James Levine . NEAT can vary between individuals up to 2000 kcal per day. According to Dr. Levine, individuals with obesity sit for 2.5 h per day more than sedentary lean counterparts. To reverse obesity, an approach he recommends is to develop individual strategies to promote standing and ambulating time by 2.5 h per day.
It is now possible to equip an office to allow standing or moving while working. There are standing desks, anti-fatigue mats, workplace treadmills, and even workplace bikes (stand-alone or under-desk). There are contraptions that can hold a computer monitor, keyboard, and mouse and enable a sit/stand solution in any home office or workspace at reasonable cost. Individuals can even create their own.
In addition, there has been an explosion of fitness trackers that can be useful to decrease sedentary time. Further, most modern smart phones now have integrated technology to track movement.
Instead of the individual completing a long workday and finding there was no time (or energy) for a workout at the gym, the individual can complete that same workday and achieve many hours of active time, potentially also mitigating the risks of excess sitting.
To date, we do not have an adequate prospective trial proving that these interventions are effective. However, as a clinician with over 14 years of experience in helping patients not only lose weight but also keep it off, it is my observation that decreasing sedentary time not only enhances the odds of success but also improves motivation and decreases appetite. Sitting at a desk results in mindless eating, especially if the food is nearby . Conversely, most individuals aren’t accustomed to eating while standing or while walking. In fact, many report that this activity suppresses appetite, perhaps by enhancing norepinephrine activity in the POMC area (pro-opiomelanocortin receptor or appetite regulation center of the hypothalamus). Further, it is my opinion that standing or moving improves energy levels compared with sitting.
I would propose that this would be an exciting area to research. But for now, given the known health risks of excess sitting, a common-sense recommendation to individuals who have lost weight, in lieu of recommending “exercise more” should be to “sit less.” After all, isn’t this one of the reasons to lose weight in the first place?