Time-restricted eating for weight loss

We asked Dr Shane to explore whether time-restricted eating (TRE) is an effective strategy for weight loss.

What is time restricted eating?

Time-restricted eating (TRE) is a nutritional intervention wherein food intake is limited to a consistent daily window without changes in nutritional quality or quantity.1 Usually, seen as a 8 to 12 hour daytime eating window and fast (no food) during the remaining 12 to 16 hours. Dissimilar to intermittent fasting, which involves caloric restriction, time-restricted eating permits us to eat as much as we want during the eating window.

Time-restricted eating and our health?

With increasing rates of obesity alongside the issues related to obesity including cardiovascular disease, stroke, type 2 diabetes, and certain types of cancers. Researchers and practitioners are looking at all potential avenues to help reduce these health issues which represent some of the leading causes of preventable death. Time-restricted eating has been shown in studies in humans to offer a novel method to prevent or reverse these metabolic diseases.

Previous Research Findings

Studies have shown: 1) that eating three standard meals within a six hour window compared to a twelve hour window resulted in a decrease in appetite and increase in fat metabolism.2 2) a three percent weight loss in a group of obese people who, for 12 weeks, restricted the eating to an 8-hour window.3 3) reductions in blood  pressure and circulating insulin levels with time-restricted eating in people who followed a 6-hour eating period, with dinner before 3 pm.4

The Importance of Exercise

Time-restricted eating has shown promise as a way of eating without restricting food that has positive effects on markers of our health. We don’t need to consider what we eat (though we should be always seeking healthy wholefood options), we just need to bookend when we eat. Some studies have reported weight loss because of time-restricted eating. First thoughts would indicate that this is ideal, especially in individuals that need to reduce their fat mass. However, we need to preserve lean body mass, or specifically muscle mass, especially as we age.

This is why we have chosen to focus on a study that addresses these questions. The article abstract can be view here. In the elderly, age‐related loss of muscle mass, (sarcopenia) negatively affects strength, balance, and stability, increasing risk of falls and impairing ability to perform activities of daily living such as walking, personal care, cooking, and chores.5 However, it is also important for middle aged adults as decreased muscle strength is a strong predictor of future mortality (death rate).6

Study Design

Food Intake: In summary, the researchers randomly split a group of overweight and obese middle-aged adults into two groups. The time-restricted eating group consumed their food between 12.00 noon and 8.00pm whilst the normal eating group maintained their regular meal timings.

Exercise: During the eight-week study, both groups were prescribed resistance exercise (weight training) and aerobic training. The resistance training was standardised for both groups and consisted of three different workouts, performed on non‐consecutive days, each week for 8 weeks. 50 to 60 min/day to total 300 min of moderate, or 150‐min of vigorous, physical activity per week necessary to promote or maintain weight loss was prescribed in respect to aerobic training component of the study.

Measurements: To quantify potential differences regarding time-restricted eating versus normal eating various measurements were undertaken. These included body composition, cardiometabolic biomarkers, hormones, muscle performance, energy intake, and macronutrient intake.

Study Results

The authors summarised their findings as, “an 8‐h time-restricted eating window with exercise training greatly reduces fat mass relative to a normal eating and increases lean mass in physically inactive and overweight or obese adults.”

General fitness as measured by resting heart rate and heart rate recovery following exercise was also reported to improve in the time-restricted eating group compared to normal eating. The authors emphasised the value of the use of time-restricted eating with exercise training as a short‐term dietary strategy for reducing fat mass and increasing lean mass in physically inactive and overweight or obese adults.

Implications of the study

It is reported that almost two thirds of all UK adults are on a diet at any one time. Reducing food intake and/or restricting specific food groups to lose body weight is the underlying principle of every diet strategy. However, sticking to these restrictive diets long term is not without significant challenges and usually results in failure.

It appears that simply reducing the period in which you eat your usual foods every day can improve your health markers, resulting in body weight reductions. If we regularly weight train, we can minimise any muscle loss and ensure that any weight loss is fat. If this is coupled with aerobic exercise, our health status and weight loss can be increased.


  • Time-restricted eating is when we limit our food intake into a specific time period.
  • Time-restricted eating can help reduce or appetite and may result in reduced food intake.
  • Reducing the period in which we eat our usual foods every day can improve our health markers
  • Weight training alongside time-restricted eating has the potential to minimise any muscle loss and ensure that any weight loss is fat.


If you have a specific interest or would like to see a particular product or nutrient reviewed, please email your request to info@bigvits.co.uk. Educating our customers in respect to the importance of nutrients and the idiosyncrasies between formulas and products is at the heart of what we want to achieve.

This post is meant for educational purposes only and does not constitute medical or nutritional advice or act as a substitute for seeking such advice from a qualified health professional. In order to make the blog series easier to read, I have used a conversational tone in many places with personal pronouns, such as “I” and “you.” This is meant only to make it more pleasant to read, and is not meant to imply that the information constitutes any form of advice, whether personal or general.