Dietary changes may treat obesity by giving mitochondria a boost

• Obesity is a growing problem worldwide, with the United States having one of the highest levels of obesity in the world.
• Low-grade chronic inflammation, often caused by dysfunction of white blood cells called monocytes, increases the risk of many health conditions in people with obesity.
• A small-scale study has found that some dietary interventions can enhance the function of mitochondria in monocytes, reduce inflammation and modify gut bacteria.
• Further research is needed to assess whether these findings may help in the treatment of obesity.

According to the World Health Organization (WHO) , worldwide obesity rates have more than doubled over the past 30 years.

Globally, 16% of adults are now living with obesity. Formerly an issue in only high-income countries, such as the United States, where more than 40% of adults have obesity, obesity is now prevalent in middle-income countries as well.

According to current guidelines, people with obesity have a body mass index (BMI) — a measure of body fat based on height and weight — of more than 30.

What is the link between obesity and inflammation?

Obesity is linked to several health conditions , including type 2 diabetes , high blood pressure and heart disease , and some cancers.

Chronic low-grade inflammation is a feature of obesity, and research has found that monocytes — a type of white blood cell that plays a key role in immune responses — are a cause of this inflammation.

Now, a small-scale clinical trial in Mexico has found that some diets can improve the energy use of these monocytes leading to increased weight loss.

The study is published in Clinical Nutrition .

Eamon Laird, PhD , an assistant lecturer in nutrition at ATU Sligo, Ireland, who was not involved in this study, told Medical News Today that:

“The findings are very interesting as a novel pilot study for much larger and in depth studies. It provides the potential that change of diet in the form of calorie restriction, intermittent fasting, and ketogenic diet could have significant benefits both for metabolic health and the microbiome. However this is on early pilot data.”

Studying the real impact of dietary changes in obesity

The 44 participants who completed the study were aged between 18 and 60 years, with a BMI of 30 to 50 kilograms per square meter (kg/m ² ). None had any chronic diseases or mental health conditions.

The researchers divided them into four treatment groups, each of which followed a different diet for two months:

• group 1 followed a calorie restricted diet (500 kcal less than their normal diet)
• group 2 followed the same calorie restricted diet, but in an intermittent fasting pattern of 16 hours fasting to 8 hours eating time
• group 3 followed a ketogenic diet with the same calorie restriction
• group 4 followed their normal “ad libitum” diet.

At 4 follow-up visits, the participants gave fasting blood samples for analysis, were weighed and had their body composition analysed.

The researchers isolated monocytes from the samples to assess their mitochondrial function. They also analyzed their gut microbiota from stool samples.

“This clinical trial was quite small, and no previous studies have specifically examined how these dietary changes impact mitochondrial function in human monocytes to support these findings. However, there has been some evidence of changes in metabolic tissues in rodent research on calorie restriction and intermittent fasting , and in human research on the ketogenic diet ,” explained Kelsey Costa, MS, RDN , a registered dietitian nutritionist and founder of Dietitian Insights, who was not involved in the study.

Diet affects mitochondrial function

Costa explained the importance of mitochondria to MNT .

“Mitochondrial bioenergetic health refers to the efficiency and functioning of mitochondria, the powerhouses of cells responsible for producing energy,“ she said.

“This is an important aspect to consider in obesity, as dysfunctional mitochondria may contribute to a variety of health issues, such as insulin resistance, inflammation, and other metabolic disorders,” Costa explained.

In this study, the researchers found that monocytes from people on the calorie restricted, intermittent fasting and ketogenic diets had significantly increased mitochondrial function.

The diets also had a positive impact on gut bacteria.

How close is this study to a real-world scenario?

While acknowledging that these are interesting findings, Laird emphasized that additional research is needed to verify them.

“[This study used a] very strict and unique population group as they had to be free of any other chronic disease or conditions — individuals in this BMI range more often than not typically have other conditions associated with obesity such as high blood pressure, COPD [ chronic obstructive pulmonary disease ], diabetes, raised cholesterol etc., so it is already preselecting a ‘healthy’ obese group not typical in the population,” he pointed out.

“In order to really ascertain clinical significance I would like to see this study replicated but with more participants to have more power — 50:50 balance with males and females and include older adults, include obese adults with any sort of disease or condition, [which would be] closer to [a] real-world scenario,” said Laird.

Health benefits

Mir Ali, MD , a board-certified bariatric surgeon and medical director of MemorialCare Surgical Weight Loss Center at Orange Coast Medical Center in Fountain Valley, CA, who was also not involved in the current research, shared his thoughts about the study findings with MNT

He told us that “[t]his is another study showing the complex nature of obesity, and how we have much more to learn to prevent and effectively manage this growing health issue.”

Despite being a short-term, small-scale study, participants showed some health benefits, which suggest that the interventions are worth exploring further.

In addition to improved mitochondrial function, those on the restrictive diets lost weight and visceral fat — the fat that collects inside the abdomen and can cause health issues — compared with those on their normal diets.

They also had an increase in the diversity of their gut microbiota — a change that may help combat obesity .

“This study reinforces the importance of considering not just weight loss but also changes in metabolic health when it comes to dietary interventions for obesity. It also highlights the potential role of gut bacteria in regulating cellular functions and how diet can influence this relationship.”

– Kelsey Costa, MS, RDN