Meal timing for weight loss, fat loss and gaining muscle has long been a kind of turf war in the fitness/nutrition profession. Should you eat breakfast to lose weight? Are late night snacks bad? Each time one question seems to get answered, more pop up. One study may have actually provided a real answer. Maybe.
If you listen to a group of fitness and nutrition professionals have a conversation about meal timing, you might think you walked into a skirmish between the Hatfields and McCoys. It can get a little territorial.
There’s the “must eat breakfast” crowd. There’s the evening protein snack crowd. And there’s a bunch of crowds in between and all around. For me, I’m a breakfast believer and an evening protein snack believer. I also believe in the opposite of those things. It just depends on your goals, preferences, tolerances and circumstances.
However, in the turf wars around meal timing, the science cats at Vanderbilt University may have just dropped a doozy on us. They may very well have proven that breakfast matters and late night snacks are out.
Yes, weight management (that is, weight gain or loss) is dictated in large part by how many calories you take in, what those calories are made of and how many calories you burn through activity and focused exercise. But in research published in PLOS Biology in February, Kevin Kelly, Owen McGuinness, Carl Johnson and others at Vandy have shown that when matters, too. Maybe more than anyone really thought.
Metabolism is linked to your biological clock and your sleep patterns. Whether you burn fats or carbohydrates varies depending on the time of day, as well as what you’re doing. Humans are pre-programmed to (mostly) burn fat while we sleep. Apparently, skipping breakfast and snacking at night throws that off.
The study design is simple yet effective. Using middle-aged and older participants, the researchers tracked their metabolism by placing them in a whole-room respiratory chamber in two separate 56-hour sessions. The study design was a “random crossover” method.
In each of the two sessions, lunch was served at 12:30 PM and dinner at 5:45 PM. The timing of the third meal, however, was different for each. In one, the third meal was served at a time associated with breakfast, 8 AM. In the other, it was served to the same group as a late-night snack, at 10 PM. Calories and nutritional content was equivalent for both meals.
The total amount of food provided during each session was the same. The participants’ activity levels were the same in both. The only difference was meal timing. The amount of fat burned during the “breakfast” session exceeded that of the late-night snack session.
Researchers believe this was a result of the meal timing influencing the body’s fat/carbohydrate preferences. The late night snack provided readily-available nutrients, thereby delaying the fat burning during sleep. The timing of food intake, then, influences whether the body chooses stored calories and nutrients over ingested calories and nutrients.
This has much to say about eating habits. Clearly, fasting between the evening meal and the first meal of the morning will optimize weight management. That is, after all, why the first meal after waking is called “break FAST.“
Keep the faith and keep after it!
Journal Reference – Kevin Parsons Kelly, Owen P. McGuinness, Maciej Buchowski, Jacob J. Hughey, Heidi Chen, James Powers, Terry Page, Carl Hirschie Johnson. Eating breakfast and avoiding late-evening snacking sustains lipid oxidation. PLOS Biology, 2020; 18 (2): e3000622 DOI: 10.1371/journal.pbio.3000622