Losing weight is never easy, as anyone who has ever tried to can attest. The amount of discipline, willpower and motivation it requires is truly something. However, there may be something that is even harder to do than losing the weight – keeping it off in the long term. Researchers on diet and obesity have been long searching for answers as to why people tend to gain all the weight back after they work hard to lose it.
Now, a new study is giving answers to the cause of this issue. The simple answer is: your appetite. Researchers found that our bodies trigger us to eat roughly 100 calories more than normal per every two pounds of lost weight. In short – when you lose weight, you start feeling really, really hungry.
According to researcher Kevin Hall, PhD from the National Institutes of Health in Bethesda, MD, this is a significant discovery as nobody had ever quantified the numbers before. This landmark study will be published this November in the journal Obesity, and has the potential to change how obese patients are treated.
In the past, most people assume that it is a slowing of the metabolism during dieting and weight loss that causes the weight regain. However, it looks like the culprit is more this appetite increase than anything else. In fact, this appetite increase is three times more powerful than the effect of slowing metabolism. But when combined together, these two factors practically guarantee that you will put the weight back on. This causes people to hit plateaus and go backwards. In fact, it is estimated that over 80% of people who lose 10% or more of their total body weight will eventually gain it all back to become as heavy or heavier than they were before the weight loss.
This team of researchers examined the data from a recent study of a diabetes drug called Invokana, which lowers blood sugar by making the body get rid of sugar in urine. During the study, 242 people with type 2 diabetes were given either Invokana or a placebo pill for a year. Both groups lost weight in that time. The people in the placebo group lost around 2 lbs, whereas the people in the Invokana group lost an average of 7 lbs each, which is still not a substantial amount. The researchers had to figure out why the Invokana taking group had not lost more weight even though lab tests showed that they were losing around 360 calories a day from urinating. In fact, this group’s weight loss plateaued over time even though the drug was continuing to get rid of a substantial amount of calories.
The researchers developed equations that eventually figured out why this was happening. They found that the patients bodies were prompting them to eat a specific percentage more of calories to make up for the deficit that they were losing. For example, if someone who is on a 2700 calorie a day diet loses 9 lbs, their appetites would then make them want to eat about 3100 calories a day, or about 400 more calories daily than before.
There were of course, limitations to this study. The volunteers in the study all had type 2 diabetes. This could look different in healthy people.
Overall, our takeaway from this study is that it is important to realize that our bodies fight against long term weight loss and that it is not all our fault if we have trouble keeping it off. Appetite suppressants and foods that curb the appetite may play a role here.