Jason Fung's Single Best Weight Loss Tip: Don't Eat All the Time

Thanksgiving is a day of feasting, and it should be. At its best, Thanksgiving is a chance for family and friends to bond over food. But a key counterpoint to feasting is fasting—by which I mean a period of time without food, but in which one still drinks water (and possibly tea and coffee). Ecclesiastes 3:1-8 is a beautiful poem:

  1. To every thing there is a season, and a time to every purpose under the heaven:

  2. A time to be born, and a time to die; a time to plant, and a time to pluck up that which is planted;

  3. A time to kill, and a time to heal; a time to break down, and a time to build up;

  4. A time to weep, and a time to laugh; a time to mourn, and a time to dance;

  5. A time to cast away stones, and a time to gather stones together; a time to embrace, and a time to refrain from embracing;

  6. A time to get, and a time to lose; a time to keep, and a time to cast away;

  7. A time to rend, and a time to sew; a time to keep silence, and a time to speak;

  8. A time to love, and a time to hate; a time of war, and a time of peace.

To this, let me add:

A time to feast, and a time to fast.

A feast like Thanksgiving should be counterbalanced by a fast at some other time. To explain why, let me turn to Jason Fung’s blog post flagged above. I featured Jason Fung’s book The Obesity Code as the most recent book in my post “Five Books That Have Changed My Life.” Jason’s blog post “My Single Best Weight Loss Tip” summarizes the essence of the book. Let me boil things down a bit more by excerpting the key passages from Jason’s blog post.

First, Jason emphasizes the importance of insulin. This is a key theme in my posts “Obesity Is Always and Everywhere an Insulin Phenomenon” and “Forget Calorie Counting; It's the Insulin Index, Stupid.” Here is Jason:

Insulin is a fat-storing hormone. There’s nothing wrong with that – that is simply its job. When we eat, insulin goes up, signalling the body to store some food energy as body fat. When we don’t eat, then insulin goes down, signalling the body to burn this stored energy (body fat). …

The “insulin causes obesity” hypothesis is easily tested. If you give insulin to a random group of people, will they gain fat? The short answer is an emphatic “Yes!” Patients who use insulin regularly and physicians who prescribe it already know the awful truth: the more insulin you give, the more obesity you get. Numerous studies have already demonstrated this fact. Insulin causes weight gain.

In the landmark 1993 Diabetes Control and Complications Trial, researchers compared a standard dose of insulin to a high dose designed to tightly control blood sugars in type 1 diabetic patients. Large insulin doses controlled blood sugars better, but what happened to their weight? Participants in the high-dose group gained, on average, approximately 9.8 pounds (4.5 kilograms) more than participants in the standard group. More than 30 percent of patients experienced “major” weight gain!

Second Jason explains the two main determinants of one’s insulin level:

There are really only two ways that insulin increases. Either:

  1. We eat more foods that stimulate insulin

  2. We eat the same insulin-stimulating foods, but more frequently.

You can read about the foods that cause insulin spikes in my post “Forget Calorie Counting; It's the Insulin Index, Stupid.” But in this blog post, Jason is emphasizing the second point, about frequency of eating:

What was the diet of the 1970s? They were eating white bread and jam. They were eating ice cream. They were eating Oreo cookies. There were not eating whole wheat pasta. They were not eating quinoa. They were not eating kale. They were not counting calories. They were not counting net carbs. They were not even really exercising much. These people were doing everything ‘wrong’ yet, seemingly effortlessly, there was no obesity. Why? …

The answer is simple. Come closer. Listen carefully. They were not eating all the time.

It all comes down to a very simple bit of advice from Jason:

So, here’s my best single tip for weight loss. It’s so simple and obvious that even a 5 year old could have come up with it. Don’t eat all the time.

Unfortunately, most nutritional authorities tell you the exact opposite. Eat 6 times a day. Eat lots of snacks. Eat before you go to bed. Eat, eat, eat – even to lose weight! It sounds pretty stupid, because it is pretty stupid.

I would be glad for any help in identifying the study or studies behind the recommendation to eat many small meals in a day. I’d like to write a blog post analyzing those studies closely. I won’t know until I get hold of those studies to read them, but I have two suspicions:

  1. They held the amount of food constant, simply spreading it out. But in real life, I’ll bet eating more frequently tends to lead to eating more total.

  2. However thin the evidentiary value of the study, it had such an appealing message, the message spread quickly.

Don’t miss my other posts on diet and health:

I. The Basics

II. Sugar as a Slow Poison

III. Anti-Cancer Eating

IV. Eating Tips

V. Calories In/Calories Out

VI. Other Health Issues

VII. Wonkish

VIII. Debates about Particular Foods and about Exercise

IX. Gary Taubes

X. Twitter Discussions

XI. On My Interest in Diet and Health

See the last section of "Five Books That Have Changed My Life" and the podcast "Miles Kimball Explains to Tracy Alloway and Joe Weisenthal Why Losing Weight Is Like Defeating Inflation." If you want to know how I got interested in diet and health and fighting obesity and a little more about my own experience with weight gain and weight loss, see “Diana Kimball: Listening Creates Possibilities and my post "A Barycentric Autobiography. I defend the ability of economists like me to make a contribution to understanding diet and health in “On the Epistemology of Diet and Health: Miles Refuses to `Stay in His Lane’.”