Medical Bulletin 21/June/2025

Here are the top medical bulletins for the day:

Intermittent Fasting versus Calorie-Restricted Diets for Weight Loss: What Works Better?

Intermittent fasting diets appear to offer similar benefits to traditional calorie-restricted diets for weight loss and improving cardiometabolic health, according to a large analysis of clinical trial data published in The BMJ. The study also found that alternate day fasting may offer modest advantages over other intermittent fasting methods, though researchers emphasize the need for longer trials to confirm these results.

Researchers conducted a systematic review and network meta-analysis of 99 randomized clinical trials involving 6,582 adults with an average age of 45 and average BMI of 31. Nearly 90% of participants had existing health conditions. The trials, lasting from 3 to 52 weeks, compared various intermittent fasting strategies with calorie-restricted and unrestricted diets, assessing outcomes such as weight loss and cholesterol levels.

The analysis found that all intermittent fasting strategies and continuous calorie restriction led to small reductions in body weight compared to an unrestricted diet. Alternate day fasting was the only approach that showed a slight benefit over calorie restriction, with a mean additional weight loss of 1.29 kg. However, this did not meet the clinically significant threshold of 2 kg set by the authors.

Alternate day fasting was also associated with modest improvements in total and “bad” cholesterol compared to time-restricted eating, though no differences were found for blood sugar or “good” cholesterol levels.

The authors acknowledge limitations including short trial durations and varying quality, but highlight that this is one of the first reviews to compare all strategies in a comprehensive model. “The current evidence provides some indication that intermittent fasting diets have similar benefits to continuous energy restriction,” they conclude.

Reference: Semnani-Azad Z, Khan T A, Chiavaroli L, Chen V, Bhatt H A, Chen A et al. Intermittent fasting strategies and their effects on body weight and other cardiometabolic risk factors: systematic review and network meta-analysis of randomised clinical trials BMJ 2025; 389 :e082007 doi:10.1136/bmj-2024-082007

Addictive Screen Use May Be Linked to Poor Mental Health in Preteens: Study Finds

Addictive use of social media, mobile phones, and video games- but not overall screen time- is associated with worsening mental health and increased risk of suicidal thoughts and behaviors among preteens, according to a new study published in JAMA.

Concerns have grown in recent years about the effects of screen exposure on children and adolescents, especially amid rising rates of anxiety, depression, and suicidal behavior. This new study, involving nearly 4,300 children from the Adolescent Brain Cognitive Development Study, looked at signs of addictive behavior- such as compulsive use that interferes with daily life- and how those patterns evolved over four years starting at age 8.

The researchers tracked children’s use of social media, mobile phones, and video games, and assessed how their screen use aligned with behaviors commonly linked to addiction. These included statements like “I play video games so I can forget about my problems,” or “I feel the need to use social media apps more and more.” Based on responses, the team identified usage patterns and linked them to mental health data, including suicidal ideation and behaviors.

Children with high or increasingly addictive use of social media or mobile phones had two to three times greater risk of suicidal behaviors than their peers with low addictive use. Notably, total screen time alone showed no association with mental health outcomes.

“Policy efforts should move away from generic limits on screen time and instead focus on identifying and addressing addictive patterns of screen use,” said lead author Yunyu Xiao, PhD, of Weill Cornell Medicine.

Reference: Xiao Y, Meng Y, Brown TT, Keyes KM, Mann JJ. Addictive Screen Use Trajectories and Suicidal Behaviors, Suicidal Ideation, and Mental Health in US Youths. JAMA. Published online June 18, 2025. doi:10.1001/jama.2025.7829

Study Reveals How Obesity in Pregnancy Triggers Liver Disorders in Offspring

Children born to obese mothers may face an increased risk of developing metabolic disorders- even when they follow a healthy diet themselves. A new study published in Nature by researchers at the University of Bonn offers a compelling explanation: in obese mice, maternal obesity reprograms immune cells in the embryo’s liver, causing lasting disruptions to metabolic function in the offspring.

The study focused on Kupffer cells, a specialized type of macrophage that takes up permanent residence in the liver during embryonic development. These cells play a critical role not only in immune defense but also in regulating liver metabolism. “They instruct the surrounding liver cells on what to do,” explains Prof. Dr. Elvira Mass from the LIMES Institute at the University of Bonn. “In this way, they help ensure that the liver, as a central metabolic organ, performs its many tasks correctly.”

The researchers found that offspring of obese mouse mothers developed fatty liver disease shortly after birth—even when fed a normal diet. The team discovered that metabolic products from the mother activate a transcription factor in Kupffer cells during pregnancy, reprogramming them to send signals that promote fat accumulation in the liver.

To test whether this reprogramming could be reversed, the researchers genetically removed the transcription factor during pregnancy. As a result, the offspring did not develop fatty liver disease, offering a promising direction for future treatment strategies. Whether this pathway can be targeted with medication remains to be seen, and follow-up studies are underway.

“This switch is a so-called transcription factor. It controls which genes are active in Kupffer cells,” said Mass, emphasizing the precision of this molecular mechanism. The implications are far-reaching: early changes in liver programming may set the stage for lifelong health challenges.

Reference: Huang, H., Balzer, N.R., Seep, L. et al. Kupffer cell programming by maternal obesity triggers fatty liver disease. Nature (2025). https://doi.org/10.1038/s41586-025-09190-w