When To Eat

Does it matter what time of day you eat?
Why You Shouldn't Snack at Night

By Jonny Bowden PhD CNS

Depends on whom you ask. The American Dietetic Association would say no, but if you ask me, I’d definitely say yes!

Several recent studies, as well as a classic one from the ’70s, support the idea that mealtimes do matter - a lot. Most recently, researchers at Brigham and Women’s Hospital – in collaboration with Tufts University in Boston and the University of Murcia in Spain – ran a 20-week weight-loss study in Spain, where the biggest meal of the day is typically eaten around 3 pm. All participants followed the same Mediterranean-type diet plan, all slept for the same number of hours and the hunger hormone levels were comparable. Half the folks ate their heartiest meal around 3 pm or earlier, while half ate theirs after 3 pm. Participants who ate later in the day lost 22% less weight than those who ate earlier.

This is hardly the first time research has shown an effect of meal timing. A study at the Salk Institute for Biological Studies showed that mice that were limited to an eight-hour feeding period each day were much healthier (and weighed less) than mice that were allowed to eat freely anytime at all, and this was true regardless of what they actually ate. Half the mice in the study ate high-fat diets while the other half ate low-fat diets, but it didn’t matter; the mice restricted to eight hours a day gained less weight than the mice that ate at any time they pleased. And another animal study, at Northwestern University, allowed mice to eat as much weight-gaining food as they wanted, but one group ate only during the day while the other group ate only at night (when they would normally be sleeping). The day eaters gained about 20% of their initial weight, but the night eaters ballooned – gaining more than twice as much weight (a 48% increase!).

Military studies dating back to the ’70s show that men who are given an identical 2,000-calorie meal at different times of the day  had their weight significantly impacted. Those who ate the heftier meal at breakfast didn’t gain weight, but those who ate the same meal at night did.

My best advice: Follow the old rule to eat breakfast like a king, lunch like a prince and dinner like a pauper. The research shows that the time you do eat truly does make a difference.

  • Abbydoodle

    It also depends if you have genetic disorders and other diseases that impact when you eat and when your body just might burn the calories. Inborn errors of metabolism make eating and loosing weight a nightmare.

    • Laura

      Actually studies are now showing that genetics play a very insignificant role in weight gain. Epigenetic factors are much more responsible for weight gain. Also, as a microbiologist, it is disheartening to see how little is discussed about the body’s intestinal flora regarding weight gain. This is impacted from birth, with even the first meal.

      • Abbydoodle

        I don’t know what are you reading. I work with 4 of the top genetics in the world in metabolics as well as an endocrinologist, 2 nutritionists, 1 dietitian, cardiologist that works with the doctor whom wrote The China Study and several more specialists related to genetic diseases regarding diet and amino acid supplements.

        I have known both children and adults that die because of failed diets. In fact several died because of the Atkins diet that caused severe electrolyte imbalances–the patients were unaware what too much protein could do to their body and brain. One sad case was the man that died two weeks before his wedding. Trying to be buff. ER dx it as the flu—it was not. The next time he was in a coma and died within 24 hours. Partaking of Fad diets without medical oversight can and has killed people. However nobody likes to talk about those nasty facts.

        Right now companies are on the main street holding parades of all sorts along with the snake oil men selling probiotics instisting that they can cure any disorder or disease from A- to Z. Again, there have already been cases where such medication being used as a shot gun effect have harmed patients because they misdiagnosed themselves.

        It is like the story of my neighbor whom used roundup on over $10K of roses growing in back yard. He thought the chemical would know what was a weed and what was a rose….Of course it did not.

        As a microbiologist you will know more than the normal person. Do you also know which diseases automatically cause malformations of the small intestines and colon so that probiotics will not be absorbed properly? Do you see the warnings on the products advocating that the purchasers know what the product does and what it can harm?—no we do not because of too many politicians and con men giving FDA crap information. Yet there is medical reports out there warning people that if you have certain diseases do not take certain probiotics. –these are not widely spread.

        Your medical field choice allows you to operate in a silo of knowledge–that is dangerous. You should have to study the full spectrum of infectious diseases and genetic disorders and what they do the body before ever making assumptions of what plays insignificant roles of weight gain.

        I was a camp for children with a specific genetic disorder this weekend past. Your lack of education about genetics play an insignificant role on weight gain would have had you chased out of there by the hordes of parents, nurses, and geneticists. There were 13 to 15 year olds that barely weighed 90 to 100 pounds. Your lack of knowledge of mitochondria malfunctions and complex disorders that prevent weight gain have nothing to do with epigenetics.

        Your comment was meant well, however it was made in an educational vacuum and you need to gain further education of diseases both infectious and genetic.

        I have been a researcher for thirty years and know that all the answers are not known nor assumed that all can be answered by the gut. The gut may be treated synergistcaly with other treatments; however it is not the God answer to cure all disease in the world.

        • Jody

          You are misusing the word “whom”.

  • http://www.leakygutcurereview.org/ Senna Stone

    This is common sense. But, the different fad diet promote different eating patterns. Some force particular types of foods others focus on meal portions and so on. My general observation of skinny and healthy people around me is that they eat small quantities of food and take their over meals, eating slowly and for a long time. They stop when they are full listening their body signals mostly. They never maze around looking for food or snacks or tasty tidbits.

  • Laura

    Most of what you are discussing are fad diets gone wrong. I’m talking strictly genetics. Do certain people have genetic mutations that can result in obesity, sure, but this is a rare occurrence, as can be read about here http://www.hsph.harvard.edu/obesity-prevention-source/obesity-causes/genes-and-obesity/ this is only one paper. I am cooking dinner and can’t reply with more information at the time. What I want to say is that an inordinate amount of obese people will blame their ‘genetics’ (“My mom has a hard time with her weight, too.” Yada yada), When, in fact, it much more learning horrible dietary habits and a lack of exercise. I can post more of “What I am reading” when I have a few minutes. But your assumption that I have not fully done my research is far from accurate.



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