Appetite Lab Study Helps to Identify How a Popular GLP-1 Medication Works for Weight Loss

GLP-1 medications have seen a surge in popularity for weight loss and diabetes management. One such medicine, tirzepatide, targets the GIP and GLP-1 hormones, which are released after eating and stimulate insulin secretion. While tirzepatide is designed to help people who have a body mass index in the obesity or overweight range, how it actually works to reduce weight has not been determined.

In a study published June 24 in Nature Medicine, a team of researchers, including Johns Hopkins Children’s Center psychiatry researcher Susan Carnell, sought to investigate the underlying mechanisms related to tirzepatide’s ability to induce weight loss.

In the study, 114 men and women without diabetes who had a body mass index (kg/m2) from 27 to 50 were randomized to have either a blinded once-weekly injection of tirzepatide or placebo, or a once-daily injection of another GLP-1 medication, liraglutide.

After three weeks, the group that had tirzepatide successfully decreased their appetite, food cravings and tendency to overeat, compared with the other groups. Brain imaging on the participants with tirzepatide showed that activation of brain areas stimulated by high-fat, high-sugar foods and high-fat, high-carbohydrate foods was also reduced.

The researchers say the results suggest tirzepatide reduces food intake by impacting eating behavior and how the brain reacts to food.

Is Your Child a Picky Eater? Appetite Lab Study Suggests It Could Be All in Their Head

An apple or ice cream? Carrots or French fries? When your child is a picky eater, it can be frustrating to try to encourage them to eat healthy foods. However, a new Johns Hopkins Children’s Center study, funded by the National Institutes of Health and published July 18 in Scientific Reports, shows that food fussiness may be caused by the brain’s response to certain foods, and there is potential for children to change these habits.

Children’s Center researchers say food fussiness, or picky eating, can increase the risk of poor nutrition and eating disorders. In their study, led by Children’s Center pediatric psychiatry researcher Susan Carnell, Ph.D., they sought to investigate the potential biological causes of picky eating.

During the study, 51 teenagers between the ages of 14 and 18 years old kept a 24-hour dietary log and participated in additional food-related tasks, and parents completed a questionnaire about their child’s eating behaviors. All activities were used to determine the teenager’s food fussiness level. The teenagers then underwent an MRI while viewing photos of fruits and vegetables, such as carrots and celery, and high energy-density foods, such as pizza and cookies.

The MRIs showed that teenagers who were pickier eaters had lesser responses to pictures of fruits and vegetables in regions of the brain associated with the drive to consume, paired with greater responses to high energy-density foods in regions of the brain associated with reward.

The researchers say their findings suggest that fussy eating may be driven in part by the brain responding differently to the sight of these foods. Carnell adds that brain response and food intake patterns have the ability to change over time.

“I hope that understanding that fussy eating is in part driven by automatic brain responses might help diffuse anxiety and conflict around family feeding interactions and help parents and teens work together to improve eating profiles,” Carnell says.

COVID-19 Story Tip: Researchers Expect Viral Transmission of COVID-19 May Increase as Temperatures Drop

The COVID pandemic has significantly impacted many aspects of life, including behaviors that may influence body weight. Check out our recent work on effects of the pandemic on appetite, diet, and binge watching in adults, and on the food parenting behaviors of fathers as well as mothers.

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