New research sheds light on how GLP-1 obesity drugs may change food cravings

By Priyanjana Pramanik, MSc.Mar 10 2024Reviewed by Susha Cheriyedath, M.Sc.

In a recent review published in the International Journal of Obesity, researchers explored the potential of glucagon-like peptide-1 (GLP-1) analog treatments to change food preferences and consumption and reduce obesity.

They concluded that while results show that GLP-1 lowers appetite and consumption in the short term, they rely on self-reports of intake. Further studies are needed to assess weight maintenance using objective intake measurements.

Study: Changes in food preferences and ingestive behaviors after glucagon-like peptide-1 analog treatment: techniques and opportunities. Image Credit: SHISANUPONG1986 / Shutterstock

Background

Of the three primary interventions for obesity, namely surgical intervention, lifestyle changes, and medication, pharmacology has emerged as minimally invasive, promisingly effective at reducing weight, and more sustainable in the long term.

GLP-1 analog medications such as semaglutide and liraglutide are often prescribed to manage obesity. Recent studies have focused on the mechanisms underlying their effect on weight loss, specifically how they alter food preferences and consumption.

About the study

This review focused on GLP-1 analog drugs, assessing how they have been studied and synthesizing what is currently known about their effects. Authors located relevant research through the medical literature database PubMed using search terms such as ‘obesity,’ ‘semaglutide,’ ‘liraglutide,’ and ‘GLP-1 analog.’

Results were filtered to ensure that they pertained to studies with human and rodent participants and had been published within a timeframe of 25 years. Outcomes were restricted to taste preference, food consumption, weight loss, and maintenance. Information related to publication year, location, methods, results, and study type were noted.

Findings

Researchers have studied ingestion behaviors through food and drink monitors and commonly rely on verbal reports and visual analog scales to assess fullness and satiety. Self-reported data are used to assess food preferences and eating control.

Studies using functional magnetic resonance imaging (fMRI) have found that people who use GLP-1 analog drugs show lowered responses to pictures of food, particularly in brain regions associated with reward and appetite, such as the amygdala, insula, orbitofrontal cortex, and putamen.

Semaglutide appears to target circumventricular organs instead of breaching the blood-brain barrier, binding with GLP-1 receptors, and modifying food preferences by interacting with amphetamine- and cocaine-regulated transcripts and proopiomelanocortin neurons.

After semaglutide treatment, individuals lose weight for 12-18 months before their weight stabilizes during the maintenance phase. People taking semaglutide said they felt less desire for salty, spicy, high-fat, sweet, and savory foods, craved less starch and dairy, and faced less difficulty resisting cravings and controlling their food intake. However, animal studies suggest semaglutide treatment could also increase low- and mid-range sucrose consumption.

During the weight reduction phase, patients consumed smaller meals and showed lower preferences for energy-rich food, leading to less energy consumption. Studies have not reported ingestive behavior during the maintenance phase, so whether patients return to their original food habits is unknown.

Some gastrointestinal effects of semaglutide, such as diarrhea, constipation, nausea, and vomiting, have been reported, but beginning at lower medication doses has been found to address this issue.

Another GLP-1 analog drug, liraglutide, reduces hunger and increases feelings of satiation during the initial phase by binding with GLP-1 receptors in the arcuate nucleus and subcortical brain region, stimulating proopiomelanocortin neurons. It may slow gastric emptying, but how it could do so has not been established.

Conclusions

The evidence suggests that GLP-1 analog drugs alter food preferences and reduce food cravings and intake, which could lead to long-term weight loss and maintenance. However, animal studies also indicate that these drugs could increase sucrose consumption, which should be examined in humans.

Less attention has been paid to ingestive, appetitive, and consummatory behavior in the weight maintenance phase. Instead, most studies have focused on the weight loss phase, and many have asked participants to report on their own cravings, portion control, and appetite.

While such data is easier to collect, it may lead to biases related to recall and social desirability, and objective measurements are needed to understand the effects of anti-obesity drugs.

The authors note that the weight-loss effects of GLP-1 analogs are now well-established and that new medications are under development.

Understanding the behavioral mechanisms through which these drugs take effect using human and rodent studies can allow researchers and health practitioners to refine treatments and tailor interventions to the needs of individual patients, enhancing overall outcomes.

Further, focusing on the weight maintenance phase of treatment can reduce unrealistic expectations by patients and their clinicians and lead to less propagation of misinformation regarding the drugs’ long-term effects, which could threaten the willingness of people to use these medications to treat obesity in the future.