The Principles of Time Restricted Eating (TRE)
Time-restricted eating (TRE) is a dietary approach that focuses on when you eat, rather than what you eat. It involves consuming all your daily calories (without necessarily counting calories or restricting types of food) within a specific time window, typically limiting the eating window to between 4-12 hours at the same period every day and abstaining from eating during the remaining hours. This approach is a form of intermittent fasting, where you alternate between periods of eating and fasting. Outside the eating window, the consumption of water, black coffee, or tea is permitted.
The effects of TRE may be mediated by weight loss but weight loss-independent effects such as improved metabolism, and lower blood pressure have also been demonstrated.
The scientific evidence behind Time Restricted Eating
Scientific evidence exists that a 4-10 hour TRE leads to a spontaneous reduction in calorie intake, body weight (a modest reduction of around 3%), and fat mass. It improves glucose control in people with impaired glucose control, as well as insulin sensitivity & resistance and possibly glucose tolerance (limiting glucose spikes) and insulin secretion.
There is some research evidence that TRE promotes a fuel switch from glucose to fatty acids which is associated with improved energy consumption and body composition (less fat mass), as well as prevention of metabolic diseases such as prediabetes without modification of food intake.
Early TRE, where the eating window is early in the day may be particularly beneficial in individuals with insulin resistance and raised glucose levels, which is often the case in people living with overweight/obesity.
TRE could potentially significantly decrease body weight, fat mass, and wait circumference (a marker of visceral fat), particularly when combined with a calorie restricted diet.
The impact of fast diets on clinical outcomes, such as death, myocardial infarction, and heart failure needs to be further elucidated.
Finding an approach that works for you
Find a version of TRE that works for you (the practicalities can be challenging – for example, at a social event that involves food outside your eating window) and that suits you in the long term, particularly if you are insulin resistant, and have impaired glucose control as it has been demonstrated in small well-run trials (rather than in ‘the real world’) in people with elevated glucose. Research has also demonstrated some weight-loss independent improvements, thought to be due to
- Improved diet quality
- Alignment of food intake more with the natural light-dark cycle
- Less sleep deprivation
- A more favourable gut microbiome which leads to a reduction of low-grade chronic inflammation in the body
Most importantly, it seems appropriate to align dietary recommendations with your individual health status and sound scientific evidence. Stick to a regular meal pattern, follow a healthy balanced calorie reduced diet and eat earlier in the day rather than late at night because those habits that we can stick with have the potential to really exert a positive impact on our health.
For more advice, book an initial consultation at our Weight Loss Clinic.
