Metabolism at night

From circadian entrainment to blood glucose management to appetite control to sleep quality:



We’re really not made to skip breakfast and eat late at night.  Nearly every line of evidence points to this.  And now:

Is the timing of caloric intake associated with variation in diet-induced thermogenesis and in the metabolic pattern? A randomized cross-over study (Bo et al., 2015)




Study design: identical meals consumed at 8AM or 8PM, controlled for activity, fast duration, and prior meals.


Metabolism shuts down at night.  That means you’re not burning fat or building muscle.  Postprandial metabolic rate (or the thermic effect of feeding) is gimped in the evening.

Any carbs you eat at night stick around in the bloodstream longer because of the circadian regulation of insulin sensitivity (skeletal muscle is insulin resistant in the evening):



despite having more insulin in the evening!



These aren’t just “correlations.”  You don’t need to eat breakfast in the morning, but “need =/= optimization.”  If you’re hell bent on fasting AND big dinners, skip lunch.




There are many more reasons:

Meal timing and peripheral circadian clocks


Nutrient Partitioning and Afternoon Diabetes

Carb Backloading

Dopamine and breakfast

LIGHT Timing for Circadian Entrainment



calories proper








Be Sociable, Share!
  • Jack Kruse

    Not sure why this shocks anyone…….go back and read Finsen and Ott and you’d see why this is how we work. You must begin to think about food in terms of photosynthesis (and human photosynthesis). You can see the pictures (light Medicine of the Future by Jacob Liberman) of how chloroplasts stream under natural daylight, another pic done under a light source that lacked UV (many chloroplasts dropped out of their normal streaming pattern and formed a clump at one end of the cell), and a picture of chloroplasts at rest. “Illuminating the chloroplasts through a red filter, which allowed only the longer wavelengths of light through, resulted in some of the chloroplasts remaining in their normal streaming pattern, some totally dropping out of the pattern, and some beginning to shortcut the pattern. If a blue filter was used, allowing only the shorter wavelengths of light through, some of the chloroplasts again remained in their normal pattern, whilst those that were previously short-cutting moved to a different position prior to beginning their short cut. Dr Ott also found that when he added some long-wavelength ultraviolet light to the microscope light source, so that it more closely simulated sunlight, all the chloroplasts returned to their normal patterns. By the end of a normal day, chloroplasts, like people, gradually slow down, come to a stop and then remain motionless during the night time period. This is why eating post sunset is nuts. People forget chloroplasts and mitochondria are symbionat bacteria!!!!!! They are linked so this function is in us and plants. This required period of rest allows them to once again respond to light energy and resume their normal streaming pattern the following day. It appears, therefore, that altering plant cellular function by altering the light source affects the normal process of photosynthesis and the resulting cell chemistry.”

    The same book also says: “In further studies utilizing pigment epithelial cells from the retina of a rabbit’s eye, Dr Ott found that filtering out normal sunlight also caused abnormal cell function. When he used a blue filter, the cells went through all sorts of contortions, while a red filter caused apparent cell-wall weakening, followed by rupturing and the eventual death of the cell.”

    From Niels Finsen’s book Phototherapy (1901 translation of an 1894 paper):

    “Engelmann says that the Pelomyxa palustris (a kind of amoeba) contracts strongly when exposed suddenly to light, but that it quickly expands under the influence of a sudden darkness. The same author has pointed out that the rods and cones of the retina shorten in light and lengthen in darkness.”

    (Engelmann, Pfluger’s Archiv., xxxv., p498) This is how the eye clock in the retina responds and this controls all growth metabolism pathways. People seem to forget that the SCN sits between the retina and leptin receptor on this pathway…… is a semiconductive pathway loaded with the highest levels of DHA in humans. Why is this a shocker? Because you don’t understand light…….that is the answer.

    • Jack Kruse

      It amazes me how many smart people in biology are clueless. Maybe you can call UAB and clue her in Bill?

    • BoogerSanchez

      Hi crap for brains. Calories are totally fictitious-they do not exist. Energy is a mathematical abstract fiction, a NUMBER ONLY. Energy is not, itself, anything. Nuclear reactions do N-O-T transform matter into a NUMBER, energy. Matter and energy are as different as giraffes and heaven.

      Joules, BTU, calories-ALL THE SAME -units to measure the exact same mathematical fiction we call energy. Neither energy, nor its units are stuff at all. Only a number. My sources? Alan Guth’s videos, Richard Feynman’s videos and innumerable particle physicists.

      CarbSane and Guyenet are morons. Taubes is a genius.

  • TechnoTriticale

    Although the study declared the standardized meals: “high protein, low-carbohydrates”, they were 39% carb, most of which appeared to be from white bread and fruit juice. Also unclear if that’s 39% by weight or kcal.

    I’m wondering if the effects would also be seen, to a similar extent, on a high fat low carb diet that really was low carb (not to mention free of grains and fruit juice).

    While we await the results of trials that will probably never be run, I have no problem with the notion that if a meal is to be skipped make it dinner, and in general make the evening meal the smallest meal of the day.

    • This.

      “if a meal is to be skipped make it
      dinner, and in general make the evening meal the smallest meal of the


  • John

    Not shocked, dubious is more like it, about the quote by Adelle Davis. I’m sure that human has always broken fast but going back more than 10,000 years ago breakfast is hardly in the morning (not late in the evening, of course, unless one can hunt with flashlight .) When you hunt, gather or fish it’s hardly worth the trouble to try to preserve the left-over. It instead becomes the meal of the next scavenger. Such is the ecology we lived then.
    A just-so-story it seems but until new evidence turns up I incline to believe it. Circadian rhythm is surely a rule to operate by but going against the grain (aka, hormetic stress) is not unuseful. One may argue that it’s the force that brings the rhythm back into alignment.

    • “it’s hardly worth the trouble to try to preserve the left-over”

      you don’t need advanced preservation techniques to keep meat/fish good for a few days… and some HG’s (eg, Ache) are known to have big breakfasts of leftovers and fruit in the morning prior to their daily activities, hunting, etc

  • jack

    The problem is I’m always nauseous in the morning. I’ve been skipping dinner for the past 3 weeks, but still not hungry in the morning. Do you have any suggestions?

    • “I’m always nauseous in the morning”

      this seems like a problem

      suggestion: see your doctor

    • Sam

      might be cause you’re eating a lot at once time, (might be liver/gallbladder/pancreas, check them with an ultrasound though a Doctor), eat just enough, so you’re still hungry, start early, stretch, get early outside, walk… drink appetite stimulating herbs.

  • ???? ????

    Sure skeletal muscle may be more insulin resistant in the evening, but did you factor in the effect of resistance exercise? I feel it changes the playing field and offsets certain things.