An experimental treatment involving injection of engineered proteins significantly lowered body weight, blood insulin, and cholesterol levels in obese mice, rats and monkeys, according to a study published Wednesday in the US journal Science Translational Medicine.

The results could pave the way for urgently needed alternatives to bariatric surgery for treating obesity in humans -- the rates of which have nearly tripled worldwide since 1975, said researchers from the pharmaceutical company Amgen.

Previously, observations in mice, rats and humans have found that the lean ones appear to have elevated blood concentrations of a protein called GDF15 compared to their obese counterparts, they explained.

Because GDF15 breaks down too quickly in the blood and is difficult to produce in substantial quantities, the scientists generated two different versions of GDF15 that were more stable in the circulation and led to higher yields.

Both versions effectively decreased body weights for obese mice and cynomolgus monkeys.

Interestingly, Xiong and colleagues further showed that the GDF15 regimen altered food preferences in mice, leading the animals to opt for lower calorie chow when offered a choice between standard food and an extra-rich condensed-milk diet.

In contrast, untreated mice gorged themselves on the high-calorie eats.

The researchers also determined that GDF15 activated a population of nerve cells called AP neurons that make up a portion of the gut-brain axis.

"In conclusion, we demonstrated a strong effect of GDF15 in lowering body weight in obese mice and monkeys," they wrote in their conclusion.

"Our data support potential use of GDF15 in the clinic, with properties that could benefit individuals with obesity and associated metabolic comorbidities."