What is time restricted feeding? How does this diet work?

-Jan 4, Caroline Blight, Health -

Goodbye keto, hello ‘time restricted feeding’.  This dieting method touts the benefits of eating three square meals a day and no expensive ingredients, which could see it ending up at the most talked about diet plan of the year. Whilst at Lumity we don’t believe in fad diets and instead prefer to enjoy all things in moderation, we’ve decided to take a closer look. 

It’s a concept which has gained traction over the past year and looks set to be the biggest diet trend of the year – in part because it’s so easy to stick to and suits any dietary requirements – Time Restricted Feeding is certainly hot news. It challenges previous advice to eat little and often or stick to three regular meals and draws on the  intermittent fasting concept of popular diets like 5:2. It’s a diet which eliminates the need for calorie-counting, deprivation and willpower with no need to buy any fancy new foods either.

What is Time Restricted Feeding?

“Intermittent fasting (IF) became a hot trend after a popular TV documentary and accompanying book where Michael Mosely proposed the 5:2 diet which touted the benefits of restricting energy intake severely for 2 days a week but eating normally during the rest of the week,” explains nutritional therapist Natalie Lamb. “The main benefits discussed were improving insulin sensitivity and prolonging life expectancy. Time restricted feeding is a form of IF. This involves having a longer overnight fast of 12-16 hours. This may mean bringing your evening meal forward to 6pm and your breakfast back to 10am. It is believed that it is during these night hours that healing and restoration can occur.”

The Salk Institute in California is a world leader in time-restricted eating research and how forcing the body to fast for the majority of the day makes a difference to the way the body works. They found when mice were allowed to eat whatever they wanted, but only during a set time of day, even if they were given a diet high in calories, sugar and fat, they still didn’t gain the weight that they were expected to. Time-restricted feeding led to weight loss of up to 12 percent when applied to mice that were already obese. When they ate the same amount of food but over 24hrs their weight gain doubled.

“Research is mounting for preventing and treating obesity and attenuating metabolic disorders including type II diabetes, with benefits proportional to the fasting duration,” says Natalie. “A 2018 12 week pilot study in obese subjects found that 8-hour time restricted feeding produced mild caloric restriction and weight loss, without calorie counting and may offer clinical benefits by reducing blood pressure.”

Is there anyone who shouldn’t practice Time Restricted Feeding?

As the diet basically only requires you to change when you eat, rather than what you eat, almost anyone can do it. But those with a blood sugar imbalances, such as those with diabetes or polycystic ovarian syndrome (PCOS) may be advised to avoid it as eating little and often may be better for them. “During this time it may be advisable to move from a diet high in refined carbohydrates and simple sugars to one rich in fibre, protein and natural fats,” says Natalie. “Carbohydrates are great to provide a quick release of energy into the blood stream to aid our fight or flight mechanism and can provide additional benefit when exercising. However, in our more sedentary lifestyles this sharp spike in blood sugar could lead to insulin resistance, inflammation, damage to cell membranes and build-up of fat storage which is energy storage for future times of famine.”

If you have digestive issues you may find you need to extended the eating period a little to allow to eat regular mealtimes, but you can still avoid eating after dinner. “If the body expects food to arrive at particular times it is seen to produce adequate digestive enzymes to assist in efficient food breakdown at these times,” explains Natalie. “This could be of benefit to those who experience digestive issues such as bloating directly after meals or experiencing undigested food in the stools. It can also be helpful to include a multi-strain probiotic, to help your natural gut bacteria as bacterial fermentation could be causing painful gas production after meals.” We also like kombucha, and kefir. 

How to start Time Restricted Feeding

There is ongoing research to see if the time you start eating and stop again needs to be the same eat day with the thinking currently that as long as you don’t eat for 12-16hrs in 24hrs you will benefit. For many people this is easily done but simply missing breakfast. For those who are naturally hungry it could be better to eat lots in the morning and then have an early dinner at say 4pm before fasting. They best thing is this diet will work with your natural inclinations.

You also don’t need to restrict your eating time every single day, although the more frequently to you the better results you are likely to find. Dave Zinczenko, author of the top-selling book ‘The 8-Hour Diet’, recommends following time-restricted eating only three or four days a week.

While you can technically eat anything in this time and there is some evidence that higher fat diets are better as this fat is used as energy in the fasting stage, it is important to still get a full range of food groups and nutritional foods – this will help you not feel hungry in the fasting stage.

What other benefits does Time Restricted Feeding have?

A host of benefits, aside from weight and blood sugar control, have been suggested as a result of eating within a shorter window of time. They include, lower levels of inflammation, detoxification, improved heart health and immunity and less harmful effects from aging or stress. Research is still ongoing into Time Restricted Feeding, but for many it looks like the benefits could be considerable while the diet is still easy to follow.

Find out more about the circadian rhythm and how working with it helps sleep, weight loss, skin and even your hair. 


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