Time Restricted Feeding
Conditions
Keywords
Energy metabolism, skeletal muscle, protein synthesis
Brief summary
Recent research shows that timing of nutritional intake and daily periods of fasting may have important health effects. In humans, limiting daily food intake to a narrow window (typically \ 8 hours) can bring about some beneficial changes in blood concentrations of fats, sugar and the hormone insulin. It is thought that many of these changes are due to the prolonged daily fasting periods and humans will have regularly experienced prolonged fasting periods throughout evolution. In the modern era, food access is widely available and it is not uncommon for the time between breakfast and a late night snack to exceed 14 hours. We have recently shown that extending habitual daily periods of fasting to 16 hours per day also improves the ability of skeletal muscle to take up amino acids, the building blocks of protein. We are interested in studying whether a single episode of prolonged overnight fast (\ 16 hours), when compared to a normal overnight fast of 10 hours, is sufficient to stimulate skeletal muscle protein synthesis in response to dietary protein ingestion in healthy humans.
Detailed description
There is a growing interest in the cardiometabolic benefits of various intermittent fasting paradigms (such as alternate day fasting and the 5:2 fast diet), where periods of normal energy intake are punctuated by periods of energy restriction or fasting. A recent alternative to these protocols is time-restricted feeding (TRF), which limits daily food/energy intake to a narrow window (typically 8 to 10h). The major strength of TRF is that it extends the duration of overnight fast without limiting normal calorie intake. Recent evidence from both animal and human studies have shown that habitual daily periods of fasting of as little as 16h can reduce fasting insulin and triglycerides levels, protect against excessive body weight gain in response to high fat and sucrose diets, better maintain fat-free mass, and improve beta-cell responsiveness. We recently completed a 2-week TRF intervention study using the 8h fed (between 8am and 4pm)/16h fast protocol in healthy individuals and found improvements in insulin sensitivity and skeletal muscle uptake of branched chain amino acids. As we did not make measurements of muscle protein synthesis, it is not known whether a single episode of prolonged overnight fast (\ 16h) is sufficient to elicit improvements in insulin sensitivity and stimulate skeletal muscle protein synthesis in response to dietary protein ingestion. The aim of the proposed study is to investigate the effect of prolonged overnight fast (16h vs. 10h) on postprandial energy metabolism and skeletal muscle protein synthesis in healthy humans.
Interventions
OTHERShort 10hr fast
Participants will fast from 11pm the night before the study day
OTHERLong 16h fast
Participants will fast from 5pm the night before the study day
Sponsors
University of Nottingham
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
SINGLE (Subject)
Eligibility
Sex/Gender
MALE
Age
18 Years to 35 Years
Healthy volunteers
Yes
Inclusion criteria
* Male * 18-35yrs * healthy * non-smoking * physically active * no excessive weight loss in past 6 months * body mass index between 18 and 27 kg.m-2
Exclusion criteria
* body mass index under 18 and over 27 kg.m-2 * sedentary * screening bloods out of range * excessive weight loss in the past 6 months * irregular eating patterns
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Index of skeletal muscle protein synthesis (A) | 3 hours | Skeletal muscle branched chain amino acid uptake using postprandial arteriovenous differences. |
| Insulinaemic responses | 3 hours | Postprandial blood insulin iAUC |
| Whole body Insulin sensitivity | 3 hours | Postprandial blood glucose and serum insulin concentrations will be used to compute the Matsuda index of whole body insulin sensitivity. Postprandial blood glucose and serum insulin concentrations will be measured every 15mins for 3 hours in response to ingestion of a protein and dextrose drink. Serum insulin concentration (mIU/l) will be measured either with an enzyme linked immunosorbent assay or a radioimmuno assay. Blood glucose will be measured using the glucose oxidase method. |
| Glycemic responses | 3 hours | Postprandial blood glucose incremental area under the curve( iAUC) |
| Index of skeletal muscle protein synthesis (B) | 3 hours | Muscle protein synthesis will be measured 3 hours after ingestion of a protein and dextrose drink in which the milk protein has been intrinsically labelled with \[1-13C\]phenylalanine. The investigators will measure \[13C\]phenylalanine incorporation into the muscle myofibrillar protein pool during the 3 hour period from a muscle biopsy sample taken pre ingestion of the drink and a muscle biopsy taken 3 hours post ingestion. This will give a rate (%/hour) of muscle protein synthesis. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Skeletal muscle insulin sensitivity | 3 hours | Postprandial arteriovenous differences in glucose concentration. Blood glucose in arterialised and deep venous blood across the forearm will be measured using the glucose oxidase method. |
Countries
United Kingdom
Outcome results
None listed