16:8 Intermittent Fasting Reduces Blood Pressure and Inflammation in Trained Adults: 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

Researchers at the University of Palermo wanted to know whether compressing daily food intake into an 8-hour window — the 16:8 approach — would affect body composition, cardiovascular health, strength, and inflammatory markers in men who were already resistance-training regularly. This was important because most IF research at the time had been conducted in sedentary or overweight populations; this study asked whether 16:8 could benefit people who were already lean and active. For background on how 16:8 works in practice, see what is the 16:8 intermittent fasting protocol and can you build muscle while intermittent fasting.

Who Was Studied

Participant profile: All 34 participants were resistance-trained males with at least 4 years of training experience. Mean age approximately 29 years. Mean BMI approximately 23.5 (lean, athletic). All participants were healthy and free of metabolic conditions at baseline.

Crossover design: Each participant completed both the TRF and ND conditions in randomized order, separated by a washout period. This design controls for individual differences between participants and strengthens the reliability of the findings.

How 16:8 TRF worked in this study: Participants consumed all of their food between 1pm and 9pm each day, seven days per week for the full 8-week period. Outside that window, only water and non-caloric beverages were permitted. Calorie intake and macronutrient composition were matched between the TRF and ND conditions — the only difference was the timing and compression of meals.

The exercise protocol: Both conditions maintained the same resistance training program throughout — approximately 3 sessions per week of structured strength training. This controlled for the effect of exercise on outcomes and isolated the impact of meal timing.

What the Researchers Found

Blood Pressure

• The TRF group showed a statistically significant reduction in systolic blood pressure of approximately 4–5 mmHg, while the ND group showed no meaningful change.
• Diastolic blood pressure also trended lower in the TRF group, decreasing by approximately 2–3 mmHg.
• Both groups started at the same blood pressure baseline, confirming the effect was driven by TRF rather than baseline differences.

Inflammatory Markers

Three key inflammatory proteins were significantly reduced in the TRF group compared to the ND condition:

• IL-1β (interleukin-1 beta): significantly decreased in TRF — a primary driver of chronic low-grade inflammation
• IL-6 (interleukin-6): significantly decreased in TRF — linked to cardiovascular risk and metabolic dysfunction
• TNF-α (tumour necrosis factor alpha): significantly decreased in TRF — associated with insulin resistance and inflammatory disease

These reductions were not observed in the ND condition during the same period.

Body Composition

• Fat mass: significantly reduced in the TRF condition. Participants lost approximately 1.6 kg of fat mass over 8 weeks while calorie intake was matched between conditions.
• Lean mass: no significant reduction. Muscle mass was preserved despite the compressed eating window and ongoing resistance training.
• Body weight: modest overall reduction in the TRF group.

Metabolic Markers

• Blood glucose: significantly decreased in TRF compared to ND
• Insulin: significantly decreased in TRF
• IGF-1 (insulin-like growth factor 1): significantly decreased in TRF — by approximately 21% from baseline

Strength Outcomes

What Did Not Change

• Maximal strength (bench press, squat, deadlift 1RM): preserved in both conditions
• Lean body mass: no significant loss in TRF despite calorie timing restriction
• Basal metabolic rate: no significant reduction in either condition

What the Researchers Concluded

The researchers concluded that eight weeks of 16:8 time-restricted feeding, when calorie and protein intake are matched, can significantly reduce body fat, inflammatory markers, and blood pressure without impairing muscle mass or strength performance. They described TRF as a viable strategy for improving cardiovascular and metabolic health without the need for calorie restriction.

What This Means If You Fast

• Blood pressure benefits are real, not just indirect. The 4–5 mmHg systolic reduction seen in this study occurred even though calories were matched — meaning it was the timing of eating, not calorie reduction, that drove the blood pressure improvement. For people already concerned about blood pressure and fasting, this is meaningful.
• Inflammation drops without dieting. Three major inflammatory proteins dropped significantly in the TRF condition. Chronic inflammation is linked to cardiovascular disease, joint pain, metabolic dysfunction, and accelerated aging — all areas where many people report improvement after starting fasting.
• You can fast and train without losing muscle. One of the most persistent fears about intermittent fasting is muscle loss. This study — in people who trained consistently throughout — showed lean mass was preserved, consistent with what most experienced fasting practitioners observe. See can you build muscle while intermittent fasting.
• Fat loss happens even when calories are matched. The TRF group lost approximately 1.6 kg of fat in 8 weeks while eating the same total calories as the normal diet group. Meal timing itself appears to shift body composition.
• 16:8 is the entry point. This study used 1pm–9pm as the eating window, which may not suit everyone. Many practitioners shift the window earlier (e.g., 12pm–8pm or 10am–6pm) based on lifestyle. The specific hours matter less than consistently maintaining the 16-hour fast.

Study Limitations

• All-male sample. The study enrolled only resistance-trained men, limiting generalisation to women and sedentary populations. Women's hormonal responses to fasting differ meaningfully from men's, and results may not translate directly.
• Small sample size (n=34). Crossover design helps control for individual variation, but 34 participants is a small sample for drawing broad conclusions.
• Highly specific population. Participants were already lean, athletic, and experienced with resistance training — a group that may respond differently to 16:8 than overweight, sedentary, or older individuals.
• Short duration (8 weeks). Long-term effects of 16:8 on blood pressure, hormones (notably the IGF-1 and testosterone reductions), and bone density were not examined.
• Industry/bias consideration. Funding source was not explicitly reported in the abstract.
• Self-reported adherence. Food intake during the TRF window relied on participant reporting; actual calorie matching could not be independently verified.

Source

Moro T, Tinsley G, Bianco A, Marcolin G, Pacelli QF, Battaglia G, Palma A, Gentil P, Neri M, Paoli A. (2016). Effects of eight weeks of time-restricted feeding (16/8) on basal metabolism, maximal strength, body composition, inflammation, and cardiovascular risk factors in resistance-trained males. Journal of Translational Medicine, 14(1):290. PMID: 27737674

Frequently Asked Questions

Does 16:8 intermittent fasting lower blood pressure?

This study found a significant reduction of approximately 4–5 mmHg in systolic blood pressure after 8 weeks of 16:8 TRF in resistance-trained males, even when calorie intake was matched to the control condition. The reduction was statistically significant and was not observed in the normal diet group.

Does intermittent fasting reduce inflammation?

Yes — three major inflammatory markers (IL-1β, IL-6, and TNF-α) were all significantly reduced in the 16:8 TRF group in this study. Chronic low-grade inflammation is associated with cardiovascular disease, metabolic dysfunction, and many chronic conditions; reducing it is one of the most consistent benefits seen across IF research.

Will 16:8 fasting affect muscle mass in someone who lifts weights?

Based on this study, no significant muscle loss occurred in resistance-trained males following 16:8 TRF for 8 weeks. Lean mass and strength (bench press, squat, deadlift) were preserved, even though fat mass decreased.

Does fasting reduce IGF-1 and is that a concern?

IGF-1 dropped by approximately 21% in the TRF group in this study. IGF-1 supports muscle growth but is also associated with accelerated aging and increased cancer risk at higher levels. Whether the reduction seen in this 8-week study represents a health benefit or concern is a matter of ongoing research and depends heavily on baseline levels.

Is blood pressure reduction from fasting meaningful clinically?

A 4–5 mmHg reduction in systolic blood pressure is considered clinically meaningful. Meta-analyses suggest this magnitude of reduction can lower stroke risk by approximately 14% and coronary heart disease risk by approximately 9% at a population level. For individuals at the borderline of hypertension, this level of change can be the difference between needing medication and managing blood pressure through lifestyle alone.

Related Research and Articles

• Can intermittent fasting lower blood pressure?
• Does intermittent fasting reduce inflammation?
• Can you build muscle while intermittent fasting?
• What is the 16:8 intermittent fasting protocol?
• Does fasted cardio burn more fat?
• Intermittent fasting and inflammation: the research explained

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