Time-restricted eating may be the new trend, but it is far from being a new concept. What is still a topic of debate is whether or not it will work for those looking to lose weight. A study recently published in the International Journal of Obesity from researchers at the University of Mississippi sought to answer the calorie-burning question, showing that when healthy adults pair an 8-hour eating window with regular exercise, they lose more fat without losing lean mass.
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“We saw that this did lead to more fat loss and reduced body fat percentage over time when healthy adults were following both exercise with time-restricting eating compared to those who were only exercising for at least 4 weeks,” said Nadeeja Wijayatunga, assistant professor of nutrition and hospitality management. “It is important to note lean mass preservation.”
Investigating one of the most popular diets
This systematic review and meta-analysis analyzed data from 15 studies conducted on time-restricted eating with exercise from the last decade, wherein time-restricted eating was one of the many diets included in the blanket term for intermittent fasting.
“People like time-restricted eating because they feel it’s easier to adhere to because they don’t have to think too much,” said Wijayatunga. “It’s all about time, not calorie-counting or watching out for certain foods.”
In recent years, intermittent fasting has become one of the most popular diets in the United States, with around 12% of Americans trying it, according to the 2023 International Food and Health Survey.
However, the science surrounding time-restricted eating is still developing, said Michael Hays, tactical dietitian and recent Ole Miss graduate. Time-restricted dieting has been suggested to cause the loss of lean mass, which is the muscles, organs, and other tissues that make up our body.
“For some people, this may be a good technique to help with body composition goals,” Hays said. “It’s just another tool, but more studies need to come out to really understand how this works in humans.”
“In most cases, these were healthy adults,” Hays said. “They were already physically fit and already had exercise routines. When you already have athletic, lean people and you decrease their body fat percentage, that’s significant.”
“We need healthy muscles,” Wijayatunga said. “Muscles are really important for the body and for your metabolism. If we lose muscle, it may impact our metabolic systems, and it just decreases mobility overall.”
Best when paired with regular exercise
The researchers found that in this study, when paired with regular exercise, time-restricted eating did not lead to a reduction in mean mass, even among those who lost body fat. However, they caution that more research is needed to confirm these findings to understand how this would impact those who are not in shape and do not exercise regularly.
“That’s why you want to couple diet with exercise,” Hays said. “When you’re losing weight, you never want to lose lean tissue. You want to lose fat.”
“That’s something that needs to be studied,” Wijayatunga said. “What I’d recommend is implementing healthy habits in a way that you — as an individual — can maintain, with guidance from a health care professional.”
To find out more about participating in their upcoming research on how time-restricted eating affects people who are sedentary and whose body mass index indicates that they are overweight, please click here.
Intermittent Fasting And Time-Restricted Eating
According to the NIH, time-restricted eating (TRE) “reduces body weight, improves glucose tolerance, protects from hepatosteatosis, increases metabolic flexibility, reduces atherogenic lipids and blood pressure, and improves gut function and cardiometabolic health in preclinical studies”.
Intermittent fasting (IF), which focuses on when you eat rather than what you eat, has been linked to several potential health benefits, including weight loss, improved blood sugar control, and enhanced heart health.
Time-restricted eating is a type of intermittent fasting, where you limit your daily eating window to a specific period, while the remaining hours are spent fasting.
Examples of eating patterns
- 16/8 method: Eating within an 8-hour window and fasting for 16 hours.
- 5:2 diet: Eating normally for 5 days and restricting calories to 500-600 on the other 2 days.
- 14:10: Fast for 14 hours and eat within a 10-hour window.
- Alternate-day fasting: Alternating between a normal eating day and a very low-calorie day.
- Early TRE: Eating earlier in the day and ending earlier, like a 6 a.m. to 2 p.m. eating window.
- Late TRE: Eating later in the day and ending later, like an 11 a.m. to 7 p.m. eating window.
How TRE works
By limiting your eating window, you naturally consume fewer calories and allow your body to spend more time in a fasted state, which can have various metabolic benefits.
Weight Management
- Calorie Restriction: IF can lead to unintentional calorie restriction by limiting your eating window, potentially aiding in weight loss.
- Fat Burning: During fasting periods, your body may switch to burning stored fat for energy, which can contribute to weight loss.
- Hormonal Effects: IF may influence hormones like insulin and growth hormone, which play a role in metabolism and fat storage.
Metabolic Health
- Improved Insulin Sensitivity: IF can enhance your body’s sensitivity to insulin, potentially reducing the risk of type 2 diabetes and improving blood sugar control.
- Lowered Blood Sugar Levels: Studies suggest that IF can help lower blood sugar levels and improve glucose tolerance.
- Reduced Cardiovascular Risk Factors: IF may help lower cholesterol, improve blood pressure, and reduce other risk factors for heart disease.
Other Potential Benefits
- Brain Health: Some research suggests that IF may improve cognitive function, protect against age-related neurodegenerative disorders, and enhance memory.
- Cellular Repair: IF may promote cellular repair and detoxification processes, potentially leading to increased longevity and reduced risk of chronic diseases.
- Improved Gut Health: IF may positively impact gut health by increasing the diversity of gut bacteria and reducing inflammation.
- Increased Endurance: Some studies have shown that IF can improve physical performance and endurance.
- Improved Sleep: Eating according to your circadian rhythm (eating during the day and sleeping at night) can promote deep sleep.
- Reduced Oxidative Stress: IF may help reduce oxidative stress and inflammation in the body.
Summary
- Intermittent Fasting: This is a broad term that refers to various eating patterns that alternate between periods of eating and fasting.
- Time-Restricted Eating: This is a specific type of IF where you restrict your eating to a certain window of time each day, for example, eating only between 10 a.m. and 6 p.m
While safe for most people, intermittent fasting/time-restricted eating is not suitable for everyone, particularly those with certain medical conditions, eating disorders, or women who are pregnant or breastfeeding. It’s crucial to consult with a healthcare professional before starting intermittent fasting/time-restricted eating, especially if you have any underlying health issues.
As with anything you read on the internet, this article should not be construed as medical advice; please talk to your doctor or primary care provider before changing your wellness routine. WHN does not agree or disagree with any of the materials posted. This article is not intended to provide a medical diagnosis, recommendation, treatment, or endorsement. Additionally, it is not intended to malign any religion, ethnic group, club, organization, company, individual, or anyone or anything. These statements have not been evaluated by the Food and Drug Administration.
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References/Sources/Materials provided by:
TJW @ WHN
https://olemiss.edu/news/2025/3/time-restricted-eating-study/index.html
http://dx.doi.org/10.1038/s41366-024-01704-2
https://www.michiganmedicine.org/health-lab/intermittent-fasting-it-right-you.
https://www.health.harvard.edu/staying-healthy/can-intermittent-fasting-help-with-weight-loss.
https://pmc.ncbi.nlm.nih.gov/articles/PMC7262456/.
https://www.thelancet.com/journals/lanhl/article/PIIS2666-7568(24)00045-X/fulltext
https://www.sciencedirect.com/science/article/pii/S2589004224002219
