I read “The Circadian Code” by Satchin Panda not because I wanted to lose weight but because I was looking for a way to cure a sudden bout of insomnia. The book had some really interesting ideas about food which tried out for myself and eventually adopted into my eating habits.

This article is a brief summary of Part 3, Chapter 5 which covers only the bits that I’m most interested in. I’ve left out the parts which dictate what foods you allegedly should and shouldn’t eat and focused on the importance of sticking to a timed eating window.

Nutrition science is based on just 2 experiments

Panda claims that all nutritional science is based on the following 2 models:

Experiment 1: Calorie restriction

Also known as the “eat less to lose weight and be healthy” diet. This was done in the early 20th century and has resulted in the popular dieting strategy of counting calories.

Experiment 2: The healthy diet

Also known as the “don’t eat junk food” diet. This one shows that the nutritional content of the food you eat is significant when it comes to weight loss and overall health.

Panda’s experiments were a bit different

Experiments on human diet usually involve feeding mice various foods and seeing which ones get fat, and although Panda’s experiments involved mice they were different in that they focused on the eating habits rather than the food itself.

We wanted to know how much of their disease was due to the poor diet and how much was due to poor eating habits

What are the results of the time restricted eating experiment?

Panda’s experiment involved a restriction of time allowed for eating. One set of mice ate small meals spread throughout the day and night while another set of mice ate meals within an 8 hour period. Both sets of mice had the quantity of food.

When the experiment was over the time restricted mice:

These results established the idea that it’s not only how much we eat and what we eat, but when we eat that matters, especially for long-term positive health outcomes.

We believe that a shortened feeding period provides the digestive system the right amount of time to perform its function uninterrupted by a new influx of food, and enough time to repair and rejuvenate, supporting the growth of healthy bacteria in the gut

The experiment was tested with 9, 10, and 12 hour eating windows and similar results were found. They also did the experiment on humans and saw similar results.

Eating like a shift worker is dangerous to your health

In the same way that it’s better not to sleep like a shift worker, it’s significantly healthier not to eat like one.

If the circadian clocks in our brains are sensitive to light then the ones in our gut, liver, heart, and kidneys are sensitive to food.

An experiment in 2015 with 156 participants showed that most people ate like a shift worker but didn’t even realise it. They all thought they ate within a 12 hour window but often delayed their breakfast by a couple of hours and overlooked late night snacks or alcohol. As far as your body in concerned, a handful of nuts before bed is just another meal.

What is the best eating window?

The optimum eating window is between 8 and 11 hours according to Panda’s research. This is because the health benefits that you get from eating within a 12-hour window double at 11 hours, and double again at 10, and so on, until you reach an 8-hour window.

My observations on trying time restricted eating

Overall I’ve found it a positive experience and have chosen to continue time restricted eating for the long term. Here is what I’ve found so far:

I’ve don’t feel hungry in between meals

Once I’d established a strict eating routine I found I stopped feeling hungry unless it was time to eat. Obviously this is great because being hungry is an uncomfortable feeling but it has an added bonus of making it easier to avoid the temptation of unnecessary snacking or eating just because I was bored.

I shit on a schedule

I had always assumed it was normal for my body to take shits somewhat randomly but since trying time restricted eating all that has changed. Now I can predict when I need to go with surprising accuracy. This has turned out to be pretty convenient when travelling or simply scheduling my day.

I eat larger meals

The size of my meals has certainly increased while doing time restricted eating and I think that’s understandable as I’m just preparing for a stretch without food. However, I have noticed that eating larger meals means that if I do break the rules and sneak an extra meal into my day then it’ll surely be a huge one and probably involve desert too if there’s any nearby.

It’s easier to plan your eating and shopping habits

I have a bowel of cold potatoes in the fridge which I know will last me exactly 2 days because I can see that it is exactly 4 portions. But before time restricted eating it might be 3.5 portions if I decide to munch on a couple of them for a snack. Shopping and meal prep gets easier if you know exactly what you are going to eat each day.