16:8 Time-Restricted Eating Improved Lung Function (FEV1) in Overweight Women: What the Research Shows

16:8 Time-Restricted Eating Improved Lung Function (FEV1) in Overweight Women: What the Research Shows

Medical disclaimer: This article summarises published research for informational purposes only. It is not medical advice and is not a substitute for guidance from a qualified health professional. Always consult your doctor before starting any fasting protocol, especially if you have an existing health condition or take medication.

Study at a Glance

What This Study Looked At

Most time-restricted eating (TRE) research focuses on weight, blood sugar, or blood pressure — but this 2024 French research team asked a different question: can compressing your eating window into 8 hours a day actually change how well your lungs work? They also tracked balance, sleep, and heart rate variability, since fasting is sometimes assumed to be dangerous for people with existing health conditions rather than something that might improve day-to-day physical function. This is a useful complement to prior fasting-and-respiratory research, which has mostly looked at asthma patients rather than general lung capacity in people without diagnosed lung disease.

Who Was Studied

Participant profile: All 31 participants were women with overweight or obesity (BMI over 25 kg/m²), free from known cardiovascular disease, and not pregnant. The TRE group averaged 28.7 ± 9.3 years old, 88.3 ± 13.4 kg, and a BMI of 32.7 ± 5.2 kg/m². The control group averaged 36.3 ± 11.5 years old, 90.9 ± 19.0 kg, and a BMI of 33.7 ± 6.2 kg/m² — none had a diagnosed respiratory condition such as asthma.

How the protocol worked: Before and after the 12-week period, researchers measured spirometry (FVC, FEV1, and the FEV1/FVC ratio) in both sitting and lying-down positions, heart rate variability, objective sleep via wrist actigraphy plus the Epworth Sleepiness Scale for daytime sleepiness, and postural balance using the Y Balance Test (YBT), a standard clinical test of dynamic balance and stability.

What the Researchers Found

Lung Function (FEV1) Improved Only With TRE

• FEV1 — the volume of air a person can forcefully exhale in one second — improved significantly in the TRE group in both body positions, while the control group showed no comparable change.
• This is one of the first controlled human trials to link a standard 16:8 time-restricted eating pattern to a measurable improvement in a core spirometry outcome, rather than just weight or metabolic markers.

Postural Balance Also Improved

• Y Balance Test scores improved in the TRE group compared to the control group in the anterior direction (p = 0.03).
• Postero-medial balance improved significantly in the TRE group (p = 0.04).
• Postero-lateral balance showed the largest improvement in the TRE group (p = 0.003).

What Did Not Change

• Heart rate variability (HRV) was not negatively affected by the 16:8 protocol — TRE did not appear to stress the autonomic nervous system.
• Objective sleep parameters measured by actigraphy did not worsen with TRE.
• The study's headline result centered specifically on FEV1; other spirometry values (FVC and the FEV1/FVC ratio) were not reported as showing the same statistically significant improvement.

What the Researchers Concluded

The authors concluded that a 12-week ad libitum 16:8 time-restricted eating protocol is a feasible and safe dietary intervention that produced measurable improvements in lung function (FEV1) and postural balance in overweight and obese women, without any negative impact on heart rate variability or objective sleep.

What This Means If You Fast

• Lung function benefits may extend beyond weight loss headlines. This trial suggests TRE's effects on the body may go further than the scale, though the exact mechanism connecting an 8-hour eating window to improved FEV1 wasn't established here.
• This was not an asthma or lung-disease study. Participants had no diagnosed respiratory condition, so these findings say more about general pulmonary capacity than about managing asthma — a separate Ramadan fasting study in 120 asthma patients found fasting did not significantly change lung function either way in people who already had asthma.
• Balance improvements are a novel and encouraging signal. Better dynamic balance could matter for fall risk and functional fitness, particularly as more research explores fasting outside of purely metabolic outcomes.
• Sleep and heart rhythm were not disrupted. If you're worried that skipping breakfast or dinner might harm sleep quality or put stress on your heart, this study found no evidence of that over 12 weeks — consistent with other research on whether intermittent fasting affects sleep.
• Talk to your doctor if you have a diagnosed lung or heart condition first. With no participants who had asthma, COPD, or cardiovascular disease, these results can't be assumed to apply to people managing those conditions — see general guidance on whether intermittent fasting is dangerous for existing health issues.

Study Limitations

• Very small sample size (31 total, split 15 vs. 16), which limits statistical power and how confidently the findings generalize.
• Women-only study population — results may not apply to men or to older or younger age groups given the notable age difference between groups (28.7 vs. 36.3 years on average).
• Short duration (12 weeks) — long-term effects on lung function and balance are unknown.
• Participants had overweight/obesity but no diagnosed respiratory disease, so the findings do not directly address asthma, COPD, or other lung conditions.
• The eating pattern was ad libitum (no calorie counting), so changes in food intake, weight, or diet quality alongside the eating-window change were not isolated as the cause.
• Available sources did not clearly confirm whether group allocation was randomized, and funding and conflict-of-interest disclosures were not accessible at the time of writing.

Source

Miladi S, Hammouda O, Ameur R, Miladi SC, Feki W, Driss T. (2024). Time-Restricted Eating Benefits on Pulmonary Function and Postural Balance in Overweight or Obese Women. Nutrients, 16(17), 2919. PMID: 39275235

Frequently Asked Questions

Does time-restricted eating improve lung function?

In this 2024 trial of 31 women, a 12-week 16:8 time-restricted eating schedule significantly improved FEV1 (the amount of air exhaled in one second) in both sitting and lying-down positions, while a control group eating normally showed no such change.

Was this study specifically about asthma?

No. Participants were overweight or obese women with no diagnosed respiratory disease. A separate 2022 cohort study of 120 asthma patients following Ramadan fasting found no significant change in lung function or asthma severity either way.

How was the time-restricted eating protocol structured?

Participants in the TRE group fasted for 16 hours and ate freely (without counting calories) during an 8-hour daily window, for a total of 12 weeks.

Did fasting improve balance too?

Yes. Using the Y Balance Test, the TRE group showed significant improvements compared to the control group in three directions: anterior (p = 0.03), postero-medial (p = 0.04), and postero-lateral (p = 0.003).

Is 16:8 fasting safe for sleep and heart health based on this study?

The researchers found no significant negative effects on heart rate variability or objective sleep measurements after 12 weeks of the 16:8 protocol, suggesting it did not disrupt these systems in this group of women.

Related Research and Articles

• Ramadan fasting and asthma in 120 patients
• Alternate-day fasting and oxidative stress in asthma patients
• Does intermittent fasting affect sleep?
• Is intermittent fasting dangerous?
• What is extended fasting and is it safe?
• Does intermittent fasting reduce inflammation?
• Does fasting improve brain function and focus?

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