Does what time you eat matter?
Biology says one thing, psychology says another
Post summary
New research in the field of “chrononutrition” suggests there are optimal times of the day to eat. Timing our meals, this research suggests, could enhance weight loss, improve health markers, and reduce hunger.
But there’s a problem: The study recommendations conflict with human behavior and, in some cases, could cause more harm than good.
We’ll unpack this field and leverage research from biology and psychology to give tactics for seven different nutrition goals.
You’ll learn how to leverage the information for weight loss, overall health, athletic performance, hunger control, and more.
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The post
Humans evolved to eat more food rather than less and prefer calorie-dense food. This helped us survive in the past when food was scarcer.
But our food drives often backfire in a world now filled with readily available food that is more calorie-packed than anything our ancestors could have ever dreamed of.
I consider this a “good problem.” Having too much food is far better than not enough; starvation will kill you quicker than diabetes.
But it’s a problem nonetheless, with (over)nutrition being the primary driver of our massive rates of chronic diseases like heart disease and diabetes.
Hence, scientists are researching all sorts of tactics that might help us eat in a way that improves our health.
One of these is “chrononutrition,” a fancy word for research investigating whether we should eat more food in the morning or evening.
It leans into the idea that we have a sort of internal clock called “circadian rhythms,” where our bodies are best suited to perform certain duties at specific times.
The chrononutrition scientists believe that when we eat does indeed matter. And the field has gotten lots of hype lately, with big stories in the Washington Post and New York Times.
But the takeaways of the research and the popular stories around chrononutrition often clash with real life. And if we follow those takeaways, we could end up worse off.
Today you’ll learn:
What chrononutrition has found about eating a big breakfast versus a big dinner.
The good and bad of chrononutrition.
When chrononutrition recommendations clash with real life.
Seven ways to blend findings from chrononutrition and psychology to eat for your nutrition goals. For example, weight loss, overall health, athletic performance, less hunger, etc.
Let’s roll …
The debate: big breakfast or big dinner?
The chrononutrition field is finding that eating a bigger breakfast is better. This seems to be because our metabolisms are more powerful in the morning. But how much more powerful?
A new, very-hyped piece of research in Obesity Reviews looked into just that.
The researchers analyzed nine studies and found that people who ate a bigger breakfast and smaller dinner lost more weight on average than those who did the opposite.
It also found that the bigger breakfast group had bigger improvements in their blood sugar, cholesterol levels, and insulin sensitivity. Those are markers for diabetes and heart disease risk.
The Washington Post said the study’s takeaway is that it’s likely “optimal” for weight and health to eat a big breakfast, modest lunch, and small dinner.
But if you peel back the layers of the study—and I did—you’ll find that the effect wasn’t a grand slam. It was a slight edge.
Five of the nine studies showed that big breakfast eaters lost more weight. Four found no real difference.
The same happened with markers for disease. Roughly half of the studies showed the breakfast group had greater improvements in their disease markers. The other half didn’t.
The thing we must always remember with markers is this: they tell us about risk for disease, but they don’t confirm actual disease.
Markers like blood sugar, cholesterol levels, and insulin sensitivity are all related to diabetes and heart disease risk. Most studies, however, don’t look at whether participants actually become diabetic or keel over from heart disease.
Just because any given health marker moves slightly in one direction or another doesn’t mean we’ll be affected—especially if that health marker doesn’t get too high.
One upside of this (sort of flawed) research
Hunger sucks! And in most of the studies, the participants who ate a smaller breakfast were hungrier throughout the day. The same was found in another recent study.
This isn’t surprising—but it is helpful for people who struggle with hunger.
Eating more food earlier in the day will lead you to be hungry for fewer waking hours. On the flip side, eating a tiny breakfast will lead you to be hungrier during more of your waking hours. And if you’re hungrier for more waking hours, you’ll probably be more likely to snack mindlessly.
Frequent snacking is associated with weight gain, mostly because we tend to snack on stuff like pastries, chips, and other junk.
When biology clashes with psychology
I do believe the slight edge is real. It probably is “optimal” to eat a bigger breakfast and a smaller dinner. It might alter our metabolism and some chemicals in our bodies in a way that seems better for us.
But there’s a giant catch—and it might throw all the biology findings out the window.