A newly developed weight loss drug is said to be a master of deception, tricking the body into thinking it has consumed calories by triggering the same physical responses as eating a meal. The drug, called fexaramine, suppressed weight gain and beefed up metabolism in mice and gets absorbed in the gut where it has fewer side effects, according to a study published Monday in the journal Nature Medicine.

“This pill is like an imaginary meal,” Ronald Evans, a senior author on the paper and director of the gene expression laboratory at the Salk Institute in La Jolla, California, said in a statement. “It sends out the same signals that normally happen when you eat a lot of food,” including causing the release of bile acids for digestion and altering blood sugar levels.

Unlike other appetite suppressants, fexaramine only acts in the gut, not the bloodstream, and targets a protein known as the farnesoid X receptor. The protein helps control digestion and fat and sugar storage in the body.

By contrast, Orlistat, one of the most commonly prescribed weight loss drugs on the market, works by keeping the body from absorbing about a third of the fat it consumes. Contrave, another popular prescription diet pill, is a combination of a drug used to treat alcohol and opioid dependence and one that treats depression.

Fexaramine essentially “[hijacks] the natural food signal in the body to trick it into burning calories and lower systemic glucose levels,” Michael Downes, a co-author on the study, told the Guardian. The drug has so far proved effective in obese mice, but researchers say the drug has shown promise for human trials.

Since 2012, the U.S. Food and Drug Administration has approved four prescription drugs for fighting obesity. Belviq and Qsymia were sanctioned two years ago, the first weight loss drugs to get the government’s stamp of approval in 13 years. Newer drugs typically have fewer side effects than older diet pills, according to Kaiser Health News, and are usually prescribed to people whose body mass indexes are 30 or higher. Most diet pills work by suppressing appetite one way or another.

Obesity rates in the U.S. have continued to soar. Last year, every state in the country had an obesity rate of 20 percent or higher. The American Medical Association formally categorized obesity as a disease in 2013, representing a break from earlier thinking that obesity was mostly a result of choice. "At least half of the risk of obesity is inherited," Ted Kyle, advocate for the research organization Obesity Society, told Kaiser.

Despite advances in both the efficacy of diet drugs as well as medical research, a third of U.S. insurance companies do not cover anti-obesity drugs, Kaiser noted. The reluctance has stemmed in part from complications with earlier forms of weight loss drugs.

Not all drugs that regulate obesity in mice are as effective in humans, according to the Guardian. Many drugs aimed at curbing weight gain never make it to market because the results often cannot be replicated in human experiments. “While [the findings of the new study] are interesting observations, only a modest percentage of drugs that seem effective in mice ever make it into the clinic for patients,” Sir Stephen O’Rahilly, a professor at Cambridge University in the U.K., told the Guardian.