Clinical trials found that timing matters when it comes to your biggest meal of the day
People tend to follow a pattern when it comes to meal planning.
Some cram most of their daily calories into a big breakfast, lunch, or dinner.
Others eat roughly equal meals while some “graze” lightly through the day.
If, like many people, you eat one larger meal daily — breakfast, lunch, or dinner — does it matter which you choose?
Let’s look at three clinical trials that reported remarkably similar results in response to this question.
#1 — Israeli trial: Big breakfasts aid weight loss and deter diabetes
Four years ago, Israeli researchers published a clinical trial they conducted among overweight and obese volunteers.
The goal was to find ways around the fact that although dieting often yields weight loss, most people regain their lost weight pretty rapidly (Jakubowicz D et al. 2013).
That’s in part because weight loss triggers an appetite-stimulating hormone called ghrelin — in contrast to having a full stomach, which triggers the appetite-curbing hormone called leptin.
So, a team at Tel Aviv University decided to test whether a big breakfast would overcome these changes and prevent weight regain.
They recruited 93 obese women for their 12-week clinical trial, and randomly assigned them to one of two groups, based on when during the day they would eat most of those calories:
- Big Breakfast: 700 calories at breakfast, 500 at lunch, and 200 at dinner.
Big Dinner: 200 calories at breakfast, 500 at lunch, and 700 at dinner.
To ensure a fair contest, the foods provided for the 700-calories meal were similar.
For example, the big breakfast group ate a dessert-type food such as a cookie as part of their 700-calorie breakfast.
At the end of the 12-week trial, everyone had lost weight and inches around their waistlines.
However, the big breakfast group did better, losing an average of 17.8 pounds and 3 inches around their waist, and they kept it off longer. In contrast, the big dinner group lost only 7.3 pounds and 1.4 inches.
Why the big difference in weight and inches lost?
The big-breakfast group showed lower levels of hunger-stimulating ghrelin, leaving them more satisfied and diminishing the desire for midday snacking seen in the small-breakfast/big-dinner group.
And the health benefits to the big breakfast group extended well beyond pounds and inches lost.
The big-breakfast group also enjoyed lower blood levels of insulin, glucose, and triglycerides (fats): benefits that should reduce your risks for heart disease, high blood pressure, and diabetes.
Lead author Daniela Jakubowicz believes people should eat a solid breakfast to optimize weight loss and general health.
And, she adds, late-night snacking is known to raise the risk of obesity, diabetes, and cardiovascular disease.
#2 — Spanish-American trial: Early lunch nets similar results
Also in 2013, researchers from Boston and Spain published a larger study that focused on lunch timing.
The international trial involved 420 overweight participants who followed a 20-week weight-loss program in Spain (Garaulet M et al. 2013).
Because of its location, the trial's design reflected the fact that Mediterranean people tend to eat lunch and dinner later than Americans do.
The participants were split into two groups:
- Later lunch — after 3:00 pm
- Earlier lunch — before 3:00 pm
In both cases, the participants consumed 40% of each day’s total calories at lunch.
After the five-month study, the team found that early-lunchers lost significantly more weight than late-lunchers, and they lost it faster.
And the late-lunchers suffered lower insulin sensitivity — a top a risk factor for diabetes.
The timing of the participants’ other, smaller meals didn’t seem to affect weight loss either way.
However, the Spanish-American team noted that the late-lunchers tended to eat smaller breakfasts, or to skip breakfast completely, which may have also negatively affected their ability to lose weight.
Lead author Frank Scheer, Ph.D., of Harvard Medical School summarized their findings: “Our results indicate that late eaters displayed a slower weight-loss rate and lost significantly less weight than early eaters ...”.
Presumably, the results would hold true in the American meal pattern — with an early lunch being one eaten before 1:00 pm, and a later lunch being one downed after 1:00 pm.
#3 — High-calorie lunch worked better than high-calorie dinner
Last year, a British-Iranian team published a trial that tested the effects of different kinds of breakfast.
The trial was designed to compare the effect of a high-calorie lunch versus a high-calorie dinner on weight loss and key health risk factors in women (Madjd A et al. 2016).
Eighty overweight and obese women aged 18-45 were asked to eat their largest meal either at lunch or at dinner for 12 weeks while on a weight-loss program.
Both groups showed significant improvements in cardio-metabolic risk factors, but the lunch group enjoyed greater average weight loss (13 lbs), lower body mass indices, less insulin resistance, and lower insulin levels.
As the British-Iranian team wrote, "... higher energy [calorie] intake at lunch compared with at dinner may result in favorable changes in weight loss in overweight and obese women ...".
Distance yourself from big dinners
What’s the take-away from this clinical research?
In short, big dinners, after-dinner snacks/desserts, and late lunches are not your friends.
To lose weight and help your overall health, enjoy a fairly hefty and well-balanced breakfast — or a large, early lunch — and avoid diving into a big dinner.
- Garaulet M, Gómez-Abellán P, Alburquerque-Béjar JJ, Lee YC, Ordovás JM, Scheer FA. Timing of food intake predicts weight loss effectiveness. Int J Obes (Lond). 2013 Apr;37(4):604-11. doi: 10.1038/ijo.2012.229. Epub 2013 Jan 29. Erratum in: Int J Obes (Lond). 2013 Apr;37(4):624.
- Jakubowicz D, Barnea M, Wainstein J, Froy O. High caloric intake at breakfast vs. dinner differentially influences weight loss of overweight and obese women. Obesity (Silver Spring). 2013 Dec;21(12):2504-12. doi: 10.1002/oby.20460. Epub 2013 Jul 2. PubMed PMID: 23512957.
- Meal timing and composition influence ghrelin levels, appetite scores and weight loss maintenance in overweight and obese adults. Steroids, 2011; DOI: 10.1016/j.steroids.2011.12.006
- Madjd A, Taylor MA, Delavari A, Malekzadeh R, Macdonald IA, Farshchi HR. Beneficial effect of high energy intake at lunch rather than dinner on weight loss in healthy obese women in a weight-loss program: a randomized clinical trial. Am J Clin Nutr. 2016 Oct;104(4):982-989. Epub 2016 Aug 31