Meal times may affect weight loss success
January 29th, 2013
05:01 AM ET

Meal times may affect weight loss success

Losing weight may not be just about WHAT you eat but WHEN you eat it, according to a new study. Participants in the study who ate a bigger meal later in the day lost less weight than those who ate earlier.

Study authors Marta Garaulet and Dr. Frank Scheer, director of the medical chronobiology program at Brigham and Women’s Hospital in Boston, followed 420 people in Spain during a 20-week weight loss treatment program.

The participants were split into two groups – early eaters who ate lunch before 3 p.m. and late eaters who ate lunch after 3 p.m. In Spain, lunch is the biggest meal of the day, comprising about 40% of a person’s daily calories.

The early eaters, on average, lost 25% more weight than the late eaters over the course of the study, according to Scheer.

The study authors found no difference in the groups’ weight loss based on breakfast and dinner timing. They also looked at energy expenditure, dietary composition, appetite hormones and sleep duration. These factors were similar in both groups, leading the authors to conclude that the timing of the large meal was the source of the sluggish weight loss.

The study was published Tuesday in the International Journal of Obesity.

Behind the results

Did you know your fat tissue has a built-in clock? In fact, the majority of cells in your body run on a 24-hour schedule, Scheer says.

The combination of all these body clocks is called the circadian system, and it’s controlled by a group of cells in your brain’s hypothalamus. But the “clocks” in individual organs’ cells can be altered by daily activity that doesn’t affect the control center.

For instance, researchers have found that feeding animals during abnormal times can “reset” the clocks in their liver and pancreas, which are key to optimizing metabolism. When this happens, the brain’s central clock remains on schedule. This can result in a de-synchronization between the two.

“That then could lead to abnormal weight gain or a decrease in weight loss,” Scheer says.

Part of this could be due to the body’s ability to handle glucose, the type of sugar that usually comes from carbohydrates. Late eaters in the study showed significantly higher HOMA levels, an index of insulin resistance that’s used to identify diabetes.

Your system is better able to cope with higher glucose levels in the morning, Scheer says, extracting sugar from the blood to use as energy. “The same meal load later in the day would not be received as well.”

Genetic link

Researchers have identified several genes that may play a role in obesity and sleep cycles – i.e. whether we’re early risers or night owls. One gene called the CLOCK gene affects our circadian rhythms. A rare variant of the gene – the “c” allele - has been linked to obesity.

This minor allele was more common in the study’s late eaters. This gene could cause them to want to eat later in the day, Scheer says.

Another explanation

The late eaters in the study often ate less for breakfast or skipped breakfast all together. Past studies have shown that’s a recipe for diet disaster. Fasting for too long can put the body into so-called “storage mode.” People who skip breakfast are also more likely to overeat later, although the study authors did not find a significant difference in the overall calories both groups ate.


There are limitations to these results. The study was observational, meaning the researchers asked participants to record their own meals. Observational studies can link two items – like meal times and weight loss – but can’t show cause and effect. The study needs to be verified with a randomized controlled trial.

That said, planning your meals for earlier in the day couldn’t hurt.

“We should really seriously consider the effect of not only what we eat, but when we eat,” Scheer says.

Try to follow the King, Prince, Pauper rule: eat breakfast like a king, lunch like a prince and dinner like a pauper.

soundoff (256 Responses)
  1. erin111

    Really, what a revelation!!!! If you don't eat late, you are slimmer..... this is what my mom told me 40 years ago.

    January 29, 2013 at 20:20 | Report abuse | Reply
  2. Manda

    Lunch after 3pm? Folks... that's called dinner.

    January 29, 2013 at 20:46 | Report abuse | Reply
    • James

      I eat breakfast when I get up which is around noon, lunch around 4 or 5 and then dinner around 8 or 9. I'm 5'11" and I weigh 160 pounds. Oh, and I always feel great and I never get sick. People are different! 🙂

      January 30, 2013 at 11:14 | Report abuse |
    • Larry

      No that's second lunch. Dinner starts at 5 p.m.

      January 30, 2013 at 12:20 | Report abuse |
  3. Disgrunteled American

    Gee and I wonder how many millions went into this study!like I knew this as a kid and for us americans after 3 is usually dinner!

    January 29, 2013 at 20:58 | Report abuse | Reply
    • Well

      Truth is there has been, until recently, absolutely no data on whether what you say you knew as a kid actually held water scientifically. What you call common sense =! scientific validity.
      There is a reason for such studies: you need to know what variables are critical so we can influence them to our favor.
      But of course, everyone with a soapbox is an armchair scientist.

      January 30, 2013 at 13:01 | Report abuse |
    • rickz70

      @Well... Certain things should not need a full study in their own right. A number of stuides have established that a) it takes time for food to digest and be passed for consumption (or storage) by your body, b) the more active you are, the more calories you burn, and c) you burn far fewer calories while sleeping. Therefore, if i consume more calories at times when they will actually hit my system while I am sleeping, I will burn fewer and store more (not to mention not getting a very good night's sleep)
      I don't disagree that there are lots of things that conventional wisdom dicatates that we haven't fully rationalized, but there was nothing about this study that even attempted to contradict the pre-existing math.

      Now, missing from this study (or at least the report) woult be a glycemic index breakdown of the calories consumed as well as activity levels (think of the old runners habit of 'bonking', carb loading, before a race). There are endless variations for timing of meals vs. impact.

      January 30, 2013 at 16:34 | Report abuse |
    • Well

      As I said, everyone is an armchair scientist.

      January 30, 2013 at 18:36 | Report abuse |
  4. bobbie walley

    In a perfect world, we could all sit down to a family meal at 4:45 pm.

    January 29, 2013 at 21:01 | Report abuse | Reply
    • karl wilder

      I am quite slim and never have dinner before 8, olives yes, not dinner.

      January 30, 2013 at 15:39 | Report abuse |
    • huh

      only when we are 75

      February 4, 2013 at 22:13 | Report abuse |
  5. TheGuy_whoLOVES_food

    I disagree!! I think it doesnt matter when you eat.

    I'm a strong believer that as long as you ingest the calories,ir doesnt matter.Like,you can eat your intire days worth of food in one sitting.

    January 29, 2013 at 21:02 | Report abuse | Reply
  6. Meal_Time

    This is MY MEAL TIME. Tell me what YOU think:

    12;30 breakfast

    2;30 lunch

    5:30 dinner

    9:45 snack

    January 29, 2013 at 21:04 | Report abuse | Reply
    • dangle13x

      I think you need to get a job.

      January 29, 2013 at 22:46 | Report abuse |
    • Glen

      You are well on your way to weight loss. Nicely done 😉

      January 29, 2013 at 23:20 | Report abuse |
    • Danny

      that is entirely too late to eat breakfast. Your body goes all night while your sleeping with no food for energy. The best way to lose weight is eating around 6 meals a day every two to three hours. It will increase your metabolism and you will never feel overly hungry. This on top of even the smallest work out plans will guarantee you weight loss.

      January 30, 2013 at 01:29 | Report abuse |
  7. Mrs Time

    What happens if you work nights? My schedule is one mess when it comes to when I work and when I am off work.

    January 29, 2013 at 21:13 | Report abuse | Reply
    • Glen

      This study is too close minded to consider such things but I have you covered 😉 As long as you have a big gap in between dinner and your first meal of the day you avoid any prolonged insulin spikes which protects you from both weight gain and keeps your blood sugar in check. Insulin sensitivity is the key to good health, if you eat before bed and as soon as you wake up it will be spiked all day taking away sensitivity and could even lead to other problems such as type 2 diabetes.

      January 29, 2013 at 23:19 | Report abuse |
  8. scranton

    And 2 + 2 = 4

    January 29, 2013 at 21:16 | Report abuse | Reply
  9. Padric22

    Pa-lease!? They need to do a "study" on this? Next month they'll be conducting tightly controlled experiments to prove that pooh smells bad. Can I get in on any of this grant money? I'd like to publish a paper proving that water is wet.

    January 29, 2013 at 21:42 | Report abuse | Reply
    • FEED ME

      when did water become wet?

      January 30, 2013 at 11:03 | Report abuse |
  10. kevin

    "The late eaters in the study often ate less for breakfast or skipped breakfast all together. "

    Most likely because they eat closer to bedtime which packs on calories when they're calorie burn is at its lowest.

    January 29, 2013 at 22:33 | Report abuse | Reply
    • Glen

      this is only true if they eat breakfast on top of that. The body burns the most fat overnight in our sleep true, but if you eat late and eat early that window is cut in half right? Which makes it very hard to burn fat no matter how much exercise is involved.

      January 29, 2013 at 23:13 | Report abuse |
  11. roike

    I love the headline on this, "what you eat may affect your weight". Really? who knew?

    January 29, 2013 at 22:45 | Report abuse | Reply
  12. Willow

    Here's a thought. How about people just exercise, instead of following weird fad diets?

    January 29, 2013 at 22:50 | Report abuse | Reply
    • Glen

      That's not enough for overweight people, they need to do both to get results. However I do agree that it can't just be a diet..

      January 29, 2013 at 23:09 | Report abuse |
    • huh

      people are so used to easy food they do not know how to shop and cook. To get into the habit of managing your own food pan menus for 2 or 3 days and shop for them and prepare them. in order to use fresh food you must shop every few days. avoid boxed, frozen or canned food. Make as much as possible. keep it simple. Bad dinner, make a scrambled egg. Make decisions about going out. When you do eat out enjoy.

      February 4, 2013 at 22:10 | Report abuse |
  13. Glen

    Just what we need, more diet advice from fat scientists and uncotrolled study groups...

    I lost weight (40 lbs) and a big part of that was by SKIPPING breakfast, yes exactly the opposite of what your mom has been telling you. When you eat a big breakfast, especially one heavy in carbohydrates, you give yourself a gigantic insulin spike that lasts the whole morning. When this happens you eliminate any fat burning coming from the previous fast and exercise and on top of that this spike makes you extremely hungry making you want to eat like an animal by lunch. By this point it doesn't matter what you eat for dinner or how much you exercise you will gain weight. INSTEAD skip breakfast, other than coffee without sugar (which helps with hunger) eat a lunch with your protein of choice and a vegetable or two (ie salad with meat or nuts) and a reasonable meal for dinner and you can only lose weight, even if you are eating a balanced 2000 calorie intake. If you are exercising you can even eat more than that and LOSE. Keep carbs very low except on days where you are training and you will have abs... just like me. I've been training in a gym on and off for over 20 years now and haven't had solid success until I have started doing exactly this and so can you.. Oh, and I eat late all the time. As long as you keep that fasting window at around 12-14 hours at least it doesn't matter how late you eat!!!

    January 29, 2013 at 23:04 | Report abuse | Reply
  14. Hugh Mann

    If you listen to cicadian rhythms, you will only eat every 17 years

    January 30, 2013 at 01:00 | Report abuse | Reply
  15. Epidi

    I'm screwed – I work nights. I also have hypothyroidism. It's all I can do just to maintain my weight, much less lose any.

    January 30, 2013 at 07:26 | Report abuse | Reply
  16. Thom

    I'm 52, 6 ft, and weigh 160. I make it a rule to never eat after 6PM. I eat my major meal before 12. My weight has been steady for years.

    January 30, 2013 at 09:17 | Report abuse | Reply
  17. Eddie

    Small frequent meals. Instead of eating 3 times a day, eat 5 regulated smaller portion meals–breakfast, lunch and small dinner and 2 snacks in between.

    January 30, 2013 at 09:51 | Report abuse | Reply
  18. Laura

    And weigh your food. I was trying to diet for a long time and couldn't lose the weight. But then I bought a kitchen scale and learned just how small a 3 oz serving of meat is. And a 1 oz serving of cheese, oh my..... Trust me, using a $15 kitchen scale will wake you up!

    I was sadly suffering portion distortion. But now with real portions, the weight came off, and I am healthier as a 40 yr old mommy than I was as a 20 yr old student.

    January 30, 2013 at 12:10 | Report abuse | Reply
  19. carly diamonds

    i eat breakfast at 6:26 am
    I have a snack in between
    I eat lunch at 1:20pm
    I eat dinner at 6pm
    when 7pm rolls around i stop eating for the day!

    January 30, 2013 at 14:53 | Report abuse | Reply
  20. robbie

    havent we been hearing "dont eat after 6 or 7 pm if u wanna lose weight" for ever?

    January 30, 2013 at 15:36 | Report abuse | Reply
  21. mirolepelt

    Yeah! that's true, but really nothing new. I also would like to mention that one of the best way to lose your weight is juicing diet http://www.squidoo.com/juice-diet-recipes2

    January 30, 2013 at 18:04 | Report abuse | Reply
  22. Argus

    The whole study is based on a lie. In Spain, they DO NOT eat the majority of their calories before 3:00! In Spain everyone eats LATE in the evening – that's the whole concept behind the spanish TAPAS. People hop from Tapas shop to Tapas shop eating and eating. And it's an evening activity, not early in the day.

    January 31, 2013 at 16:04 | Report abuse | Reply
  23. Plantiful

    It's not when you eat that affects weight, it is what you eat and how much of it, balanced by what activity you do.
    Calories IN must = Calories burned.

    Generally, Americans eat too much and do too little. No rocket science needed.

    January 31, 2013 at 16:16 | Report abuse | Reply
  24. Jim

    This does a decent job of debunking this study http://superfitdads.com/headlines-studies-dont-believe-the-hype/

    February 1, 2013 at 20:54 | Report abuse | Reply
  25. suzanne

    Did they factor in what these people ate and what their level of activity was? There is no mention of that, which would be huge factors...

    February 4, 2013 at 20:15 | Report abuse | Reply
  26. huh

    Makes sense.But Americans just eat too much. I am a tall woman of average build. I have never been more than 20 lbs overweight. I eat breakfast every morning and always include a protein. Lunch is a half sandwich or fruit and a cheese or cottage cheese. Dinner is anything I want. I am a good cook. But my portion size is small compared to what others around me are eating. I eat dinner late so I do not snack at night. I find it offensive that in a starving world Americans are killing themselves with food. Then claim discrimination.

    February 4, 2013 at 22:05 | Report abuse | Reply
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    February 11, 2013 at 02:55 | Report abuse | Reply
  28. Adrian

    I've found this article really interesting actually, I always knew what eating late isn't exactly good for you but i never knew that your body will react differently depending on the hour of day. I'm also amazed by what a difference it made in the results, I always thought that it would be a relatively small difference. Hopefully this article helps more people understand the specifics of healthy dieting.

    February 21, 2013 at 20:14 | Report abuse | Reply
  29. Scandinavian Gold

    It's not when you eat, It's WHAT you eat!
    Refined sugars, refined wheat, and prepacked foods filled with artificial flavors, artificial colors and artificial sweeteners are blocking your brain's ability to speak to your endocrine system for processing these elements from your system.
    Everything we know about dieting are myths!
    The key to losing weight and getting healthy is to detoxify, rehydrate and balancing your body chemistry, especially your pH levels.
    Our systems are blocked...you can tell just by looking at people...they look bloated, swollen almost.
    This is a sign of bad body chemistry, and NO MATTER how much you change your eating times, if you do not detoxify, you will not change your weight!
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    February 28, 2013 at 15:03 | Report abuse | Reply
  30. olivia

    beside meal times, can I use supplement like 6 extreme at http://www.p6extreme.org?

    March 6, 2013 at 04:40 | Report abuse | Reply
  31. Marko

    Thank you for the informations, this is the best way to lose weight : http://weightlosswise.blogspot.com/2013/03/EffectiveWaystoLoseWeightFast.html

    March 8, 2013 at 11:21 | Report abuse | Reply
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    Do you suffer from excess weight?
    Do you want information renewed?

    March 18, 2013 at 19:13 | Report abuse | Reply
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    March 22, 2013 at 08:11 | Report abuse | Reply
  34. Patrick Pommier

    Coming from a physiological standpoint, I agree that eating small meals (150-200 calories based on average 2,000 calorie diet) 4-5 times a day rather than 2 -3 large meals keeps your metabolism constant. Feeding our bodies throughout the day maintains our metabolism and the constant work of our caloric expenditure. When we sleep, our body obviously slows down and therefore large meals right before bed are broken down at a much slower rate than when we are awake. On the other hand, going long periods of time without consuming any fuel can also decrease the rate at which are metabolism functions. While there are many other factors to consider in weight loss (ie; what we eat, heredity and mainly caloric expenditure outside of metabolism) the time we eat our meals is just one pawn in the battle against weight gain, but always remember, eating healthy and exercising regularly 5-6 times a week can have the best impact on the amount of lean body mass vs fat body mass in our bodies.

    March 25, 2013 at 15:04 | Report abuse | Reply
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  37. Kristi

    well this all depends on the person, but after the birth of my twin almost 4 yrs ago i found myself 29 yrs old and almost 80 pounds overwieght! i just recenlty started seeing a new doctor where we recently moved to and he put me on the six meals a day, lots of water, and no eating after 7pm at the latest. he always tell me that no one will lose weight eating at 10pm at night. and i have lost almost 35 pounds in 3 months and still losing! so its working for me!

    April 20, 2013 at 14:33 | Report abuse | Reply
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