by Chris Shugart
Morning vs. Evening-Loaded Calories
When you need to lose fat, is it better to eat a bigger breakfast or a bigger dinner? Here's the new science.
I'm a big fan of breakfast. Studies show that breakfast skippers are usually more overweight than breakfast eaters. Eating breakfast controls hunger throughout the day and into the evening (if it contains plenty of protein), preventing nighttime bingeing. And if you train in the morning, fasted lifting is generally the antithesis of making gains.
Breakfast also keeps your naturally high morning cortisol under control. Cortisol levels rise sharply 30-45 minutes after waking, helping increase alertness. It's called the Cortisol Awakening Response. You want that. Without it, you'd feel groggy all day. But after cortisol does its wakey-uppy thing, you need to regulate it with breakfast so the cortisol response isn't prolonged. That can lead to stress, insulin resistance, and even muscle breakdown.
For those reasons, I always advise people to eat breakfast. But since we're nutrition nerds, we like to dig a little deeper. For example, since at least 1975, researchers have been trying to figure out the best way to distribute our daily calories. For fat loss and metabolic health, is it better to front-load calories (eat a big breakfast and a smaller dinner) or back-load calories (eat a small breakfast and a bigger dinner)?
Until recently, most studies leaned toward front-loading calories, but those studies had their flaws – small sample size, not-great measurements of body fat and lean muscle, etc. Now, we have a newer, better study that answers the big question. Here's the answer: it doesn't matter much... but it does matter a little bit.
The Study
Researchers recruited 30 overweight people to undergo 8 total weeks of calorie-restricted dieting. Half followed a front-loading approach (bigger breakfast), and half followed a back-loaded approach (bigger dinner). Both groups averaged 1750 calories daily, putting them into a 1100-calorie deficit.
Morning-Loaded Diet:
- Breakfast: 45% of total daily calories
- Lunch: 35% of calories
- Dinner: 20% of calories
Evening-Loaded Diet:
- Breakfast: 20% of total daily calories
- Lunch: 35% of calories
- Dinner: 45% of calories
After each 4-week phase, they had a week-long washout period (normal eating) and switched groups. Body composition was measured using the BodPod, DEXA, and total body water measures. There was no exercise plan.
Who Lost More Fat?
Both groups lost almost the same amount of weight, and lean mass changes were nearly identical:
- Morning-Loaded Eaters: Lost 7.3 pounds and 1.9% body fat
- Evening-Loaded Eaters: Lost 7.5 pounds and 1.8% body fat
The researchers concluded: "We demonstrate no differences in total daily energy expenditure or resting metabolic rate related to the timing of calorie distribution and no difference in weight loss."
So, Calorie Distribution Doesn't Matter?
Not according to this study of overweight folks who don't lift weights. However, remember, this was a controlled study. For example, all the subjects' calorie-controlled meals were provided. The researchers acknowledge that most people not involved in studies tend to lose weight or avoid fat gain by eating a bigger breakfast.
They attributed this to "behavioral changes" – eating a larger breakfast simply leads to greater satiety and lower hunger. So, according to them, eating a larger breakfast doesn't lead to weight loss via metabolic adaptation but rather appetite management.
In layman's terms, eating a larger breakfast isn't doing any metabolic magic, but it does help you eat less throughout the day and reduce calories. Either way, eating breakfast is a good idea. The evening-loaded dieters in this study were indeed hungrier all day, but since they were provided with meals and stuck to the plan, they didn't overeat in the evening. The question is, can a regular person stay in control?
The Protein Piece
The dieters in the study above consumed an isocaloric diet: 30% protein, 35% fat, 35% carb. How much protein is that? About 131 grams per day. Not bad compared to most studies, but none of the subjects were lifters or athletes.
To optimize muscle protein synthesis (gains, bro), a lifter needs at least .8 grams of protein per pound of body weight. So, a 200-pound guy needs at least 160 grams daily. Exceeding that amount by using the "old reliable" formula of 1 gram per pound of body weight would result in even better appetite control and increased thermogenesis (fat burning).
To easily hit your protein goals, add a protein shake or two every day. Two scoops of MD Protein (Buy at Amazon) provides 44 grams, with a big portion coming from micellar casein. Micellar casein boosts metabolic rate and muscle protein synthesis, making it a double-duty protein.
Note: Thanks to Bill Campbell, PhD, for pointing out this study in his Body by Science newsletter.
Reference
- Ruddick-Collins, L. C., et al. "Timing of Daily Calorie Loading Affects Appetite and Hunger Responses Without Changes in Energy Metabolism in Healthy Subjects with Obesity." Cell Metabolism, vol. 34, no. 10, 2022, pp. 1501-1515.e5.
