The 8-hour Diet: Eat and Still Lose Weight?

8-hour diet

The Gist of It

  • Research suggests that a 16-hour fast, followed by an 8-hour eating time period helps with weight loss.
  • This is because it provides time for your body to digest food more efficiently, while also drawing from your fat reserves, turning your body into an efficient fat burning machine.
  • Getting enough sleep also plays a large role in weight loss.
8-hour diet

While you’re busy calorie-counting and making deals with yourself on whether or not you get to munch on that cupcake, researchers at the Salk Institute for Biological Studies in La Jolla, California suggests that we’ve been doing this diet thing all wrong.

The study concluded that we shouldn’t be focused on calorie-counting but instead on when (and when not) to eat. The Salk study finds the modern lifestyle of regular activities continuing way after dark, together with consequent food consumption, leads to weight gain because food simply doesn’t get digested enough.

How it Works

The basis for the Salk study conclusion is that if you force a period of nutrient scarcity (by fasting), your body will not only digest food normally, but also draw on your reserves. This ensure only what you need stays on.

They came to this conclusion by studying, well, mice. (What else!)

Several groups of mice were given the same amount of food on different eating regimens for 100 days, mimicking the regular human diet of high-fat, high-calorie food.

Half the mice had access to food all day and night, letting them eat whenever they wanted. As you might expect, the mice simply nibbled on and off throughout the day and night, depending on their fancies. The other mice had access to food only for eight hours at night, when they were most active.

At the study’s end, researchers found the difference to be quite astonishing.

The Fasting Mice Came Out Better Off

Despite the high-fat, high-calorie diet, mice forced to fast 16 hours daily – through their sleep cycles – were found to be almost as lean as a control group with optimal calorie intake.

Mice which could eat at any time became obese instead – despite consuming the same amount of fat and calories as those fed only within the eight-hour food regimen!

Worse, the unfettered eating mice were found via autopsy to have also developed high cholesterol, high blood sugar, fatty liver disease and metabolic problems – a common consequence of being overweight.

No Signs of Disease or High Cholesterol in the Fasting Mice

This was in sharp contrast to the time-restricted feeding mice, which were found to have hardly any signs of inflammation or liver disease, and their cholesterol and blood sugar levels were virtually indistinguishable from the control group – despite the high fat and calorie intake!

Even more surprising were the results from the endurance and motor control tests conducted on all three groups of mice. Those fed fatty food, but were forced to fast, performed best on an exercise wheel – outdoing even the control group.

While a similar study has yet to be done on humans, the conclusions are nevertheless very promising – despite sceptics seeking to pour cold water on the Salk Institute finding, saying humans are exposed to too much irresistible food temptations throughout day and night.

We Don’t Give Enough Time for Our Bodies to Digest Foods

The study conclusion isn’t exactly new. There have been much advice over the years that the best way to burn up the calories you consume is to get enough sleep daily – a practice many of us fail to stick to – because your body then can digest the food properly.

Even without having to resort to any real scientific mumbo jumbo, this advice makes a lot of sense. How can the body fully digest food already consumed if more keeps getting stuffed in all the time without a proper break?

Some of Us Already Fast Intermittently

This intermittent fasting study might sound new to you, but it’s actually already being done annually by a very significant portion of the world’s population – though for only about 30 days rather than the 100 days the test mice were subjected to.

During Ramadhan, Muslims fast after sunrise, up till the sun sets. Unfortunately, the way Muslim fasting is practised these days is hardly a way to really lose weight – despite religious tenets being strictly followed.

While there has been no recent controlled study on this phenomenon of gorging before dawn and when breaking fast after sunset, a quick straw poll among Muslims conducted by Only Health magazine has found that many admit to possibly consuming double daily during Ramadan – when compared to what they would otherwise eat on regular days.

As such, any direct comparison to the Salk Institute study may not be valid as the food intake is different. Still, it is interesting to note how most Muslims did not end up being grossly overweight despite doubling food intake during Ramadan!

Pros and Cons

The Salk study suggests that intermittent fasting works because it provides the stomach, brain and body’s digestive machinery a break from managing incoming fuel. It also helps the body to avoid getting into a state of metabolic exhaustion.

But critics warn of possible unintended consequences – especially in regard to diabetes risk – falling back on a 1992 clinical trial which concluded that eating frequent, small meals resulted in better insulin control and longevity.

Also, the Salk findings could lull people into believing they don’t need to exercise to stay trim and achieve weight loss – even though there has been no such suggestion by the researchers.

On the contrary, the Salk report concluded that the modern sedentary lifestyle – with consequently longer waking hours – has resulted in higher food consumption compared to hardworking agrarian patterns before the advent of the industrial age.

Due to higher physical activity, people who lived over 200 years ago were healthier because they slept when the sun set and rose with the dawn; highlighting another key aspect to weight loss – getting enough sleep.

Test it: Intermittent Fasting

If you decide to try out intermittent fasting, make sure you’re doing it for the right reason – getting to a healthy body weight. Don’t use it as a license to gorge yourself to the max.

1. Start by first analysing how much you consume daily – and make sure you don’t eat more than that.

2. Take advantage of your body already fasting when you’re asleep. This means no digging into the refrigerator should you wake up in the middle of a bad dream.

3. Delay your breakfast to at least 10am (new studies suggest that contrary to popular belief, it’s not bad to skip or postpone breakfast). If you need to, simply consume plain water till then. With 10am being set as the starting point for food consumption, focus then on ensuring you no longer eat anything after 10pm or earlier if you can. This effectively works out to 12 hours of fasting daily with minimal fuss.

4. Once you’ve achieved this self-feeding regimen, you might want to then extend this fasting period by possibly skipping breakfast altogether and having dinner latest by 8pm. The key here is also keeping track of what you consume in-between to ensure no excess consumption.

5. No more snacks in front of the TV or milk and cookies before bed. For those who find it difficult to fall asleep without a quick bite first, drink plain water instead.

6. Continue maintaining a healthy, balanced diet filled with fruits, veggies, protein and the rest of the nutrients your body requires to function well. While the 8-hour diet MAY help you to lose weight, you still want to maintain your health, right?

7. Make sure you still exercise and stay active. Remember, our ancestors were healthier because they slept enough and had very physical lives. (And also, the mice researched on were definitely not lounging about on the couch watching TV all day long).


Have you ever tried out intermittent fasting? How has it worked out for you? Let us know in the comments below or on our Facebook page!


Edited by: The HealthWorks Team

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