Fitness influencer Diana Kadraliyeva, known for sharing home workout routines and nutrition advice, recently highlighted how changes in body composition can dramatically alter facial features.

In a June 17 video, she simulated a person’s appearance at body fat percentages ranging from 10% to 50%, sparking a heated online debate over which look was most attractive.

While some viewers described the higher body fat depiction as “cute” and criticized the 10% version as looking “gaunt” or “skeletal,” others favored the opposite.

Dr. Kevin Gendreau, MD, a Massachusetts-based, board-certified obesity medicine physician, cautioned against glorifying extremely low body fat levels, emphasizing that adipose tissue plays an essential role in overall health.

“We’ve spent decades demonizing body fat, but fat is a vital endocrine organ,” he said.

Image credits: Kateryna Hliznitsova/Unsplash (not an actual photo)

Kadraliyeva’s video began with showing a woman with 50% body fat.

She had a softer, rounder facial structure, while lower levels—ranging from 30% to 10%—showed sharper definition, including a more sculpted jawline and prominent cheekbones.

“Your face is often the first place where changes in body composition become visible,” the influencer said in the caption.

Image credits: Diana Kadraliyeva

She attributed the changes in facial features to “human physiology,” claiming a body fat range of 18% to 25% is generally considered a healthy balance for most women.

At these body fat percentages, she claimed, “facial features tend to look naturally defined without appearing either puffy or overly lean.”

She, however, did not impose the numbers on her followers and instead asked them, “At what body fat % do you think the face looks its best?”

Many agreed on 20%, while some voted for 30%.

One user, however, suggested that women “above 30 years old should have more than 30% body fat, otherwise they start looking gaunt.“

Image credits: Magnific/freepik (not an actual photo)

Another commenter said that 10% is “extremely rare and biologically difficult for women.”

“This level sits at the absolute minimum ‘essential fat’ limit required for basic human survival, making it exceptionally challenging to achieve and generally unhealthy to maintain long-term.”

“Having low body fat can k*ll you if you get sick,” a separate user commented.

Image credits: Magnific/freepik (not an actual photo)

A December 2021 study by researchers at the University of East Anglia and the Quadram Institute found that the body’s fat stores play a crucial role in helping immune cells fight microbial threats.

The team studied Salmonella, a bacterial infection that can cause symptoms such as diarrhea, vomiting, abdominal pain, fever, and, in severe cases, sepsis. 

By tracking fatty acid movement and consumption in live stem cells, researchers analyzed how the immune system responds to infection, including its impact on liver health.

Image credits: Fellipe Ditadi/Unsplash (not an actual photo)

They discovered that when an infection occurs, signals in the bone marrow — where blood stem cells are produced — cause fat cells (adipocytes) to release stored fats as high-energy fatty acids into the bloodstream. 

These fatty acids are then absorbed by blood stem cells, providing the energy needed to rapidly produce millions of white blood cells that help fight off Salmonella infections.

Image credits: Ella Olsson/Unsplasg (not an actual photo)

Dr. Stuart Rushworth of UEA’s Norwich Medical School corroborated the findings at the time, saying, “Fighting infection takes a lot of energy, and fat stores are huge energy deposits, which provide the fuel for the blood stem cells to power up the immune response.

“Working out the mechanism through which this ‘fuel boost’ works gives us new ideas on how to strengthen the body’s fight against infection in the future.”

Image credits: Kateryna Hliznitsova/Unsplash (not an actual photo)

Healthline estimates the acceptable body fat percentage at 25-31% for females and 18-24% for males. 

“Fat plays an essential role in hormone production, temperature regulation, and, of course, energy storage,” Dr. Gendreau told GQ India in March.

While he acknowledged that excessive body fat can pose a risk to one’s health, he said fixating on low body fat isn’t healthy either. 

“When body fat percentage drops too low for too long, things start to malfunction,” he said.

Paul Kriegler, a registered dietitian, personal trainer, and director of nutritional product development at Life Time, meanwhile, criticized unhealthy practices—such as starvation and GLP-1 use—that some engage in to achieve the desired result.

“Everything that needs to be done to get there and stay that low puts a lot of extra stress on the body,” he said.

“It can strain your neurotransmitter production, your mental health, your mood, your focus, your memory, your cognitive function, and your hormone production.

“Those can start to shift in a negative direction. If you’re surfing too fine a line to stay lean, something is going to give.”

“In a world where fat loss is just a few jabs away, it’s especially important to be aware of these risks,” Kriegler said.