Triglyceride and chylomicron "stacking"

Continuing the comments started in Grazing is for cattle, here's an interesting study from the Oxford Center for Diabetes, Endocrinology and Metabolism.

Volunteers were fed a test meal breakfast of Rice Krispies, a banana, and a chocolate milkshake (76.4 grams carbohydrates, 51.9 grams fat, 12.2 grams protein). Lunch was served 5 hours later and consisted of a cheese sandwich and a second chocolate milkshake 43.4 grams carbohydrates, 49.6 grams fat, 24.0 grams protein). Frequent blood samples were then assessed over the day. (Don't try this at home: These are obviously very dangerous foods!)

Here's the pattern of triglycerides that was observed (1st dotted vertical line = breakfast, 2nd dotted vertical line = lunch):

Note that triglycerides only begin to decline 3-4 hours after breakfast, only to peak higher after lunch.

Here's the pattern observed for chylomicrons, the "granddaddy" of lipoproteins that derives from intestinal absorption of fatty acids:

Both graphs from Heath RB et al Am J Phyiol Endocrinol Metab 2006.

With chylomicrons, note a similar pattern to triglycerides: Chylomicrons begin to decline at 3-4 hours, only to peak higher after lunch.

This is the first study to examine the effect of sequential meals on such postprandial (after-eating) patterns. But it makes the graphic point that, if insufficient time is permitted between meals, both triglycerides and chylomicrons will "stack" themselves higher and higher. (Chylomicrons are subjected to processing by the enzyme, lipoprotein lipase, to form highly atherogenic, or plaque-causing, chylomicron remnants.)

While not examined in this study, my bet is that "grazing," i.e., eating small meals or snacks frequently, is an extreme instance of triglyceride, chylomicron, and chylomicron remnant stacking. That can only lead to one thing: accelerated heart and vascular plaque.

Comments (24) -

  • Ross

    11/10/2009 6:02:20 PM |

    I thought that chylomicrons produced by the gut became bouyant fluffy LDL and that IDL produced by the gut became small dense LDL.  No?

    Also, it occurs to me that this "gut-produced particle clearing" phenomena could be all/part of the cholesterol benefit of intermittent fasting.  By allowing the body time to fully convert/reduce the gut produced lp particles, the body has more time to restore a homeostatic balance of blood lipid particles.

  • Jim Purdy

    11/10/2009 6:34:06 PM |

    Both meals were high-carb and high-fat. Can you be more specific in placing the blame on either the high-fat or high-carb component? I am inclined to believe that a high-fat (but low-carb) diet would not show the same stacking effect.

  • Will

    11/10/2009 7:14:27 PM |

    Hi Dr. Davis,

    So I guess that we could either not eat for approximately 7 hours after each meal (which I just kinda eyeballed from the chart where I thought that it would end up back at baseline) or eat something that does not contribute to either plasma TG or chylo concentrations. In the "Grazing" post you had replied that veggies probably wouldn't have much of a negative post-prandial effect. Would anything else be safe to eat without affecting these numbers? Probably not, LOL! Just trying to look for a practical application of this information, because If I had to go 6 or 7 hours without eating, I would have to struggle with compliance. Thanks!

  • David

    11/10/2009 7:19:09 PM |

    Nice summary, Dr. Davis.

    I eat two low carb meals per day. A small breakfast in the morning and a large dinner at the end of the day. I also fast 1-2 days per week. I am definitely in favor of spacing out meals far apart. This also helps with insulin sensitivity and weight management. Even on a low carb diet, insulin spikes when we eat. This is countered by glucagon, of course, but palmitic acid still creates a temporary (and reversible) insulin resistance for awhile after this, and it just doesn't make sense to keep feeding this cycle with frequent meals - low carb or not. It is very freeing to eat less often. You can devote your time to other things. Hunger takes care of itself once gluconeogenesis kicks in and blood sugar is under control, and you stop obsessing over food. It's great.

  • scall0way

    11/10/2009 8:04:57 PM |

    Posts like this make me glad I've changed my eating habits to eliminate all snacks and often have just two meals a day. Smile

  • Adolfo David

    11/10/2009 10:48:57 PM |

    This only probes that when one eats a glycemic meal.

  • Anonymous

    11/10/2009 11:34:03 PM |

    Hi Dr. Davis,

    Seems like these meals had high levels of both carbohydrate and fat.  Don't postprandial chylomicrons and triglycerides reflect dietary fat rather than dietary carbohydrate?


  • Gretchen

    11/10/2009 11:48:27 PM |

    I tend to graze, and I once tested the effect of grazing vs 3 meals on my blood sugar levels.

    On Day 1, I ate as I normally do (grazing), but every time I ate something, I put an equal amount of the food aside.

    On Day 2, I divided the set-aside food into three groups and ate 3 meals, with no snacks.

    Results were what you might expect. With the 3 meals, the peaks were higher, but because there was more time between meals, the blood sugar dropped lower before the next meal.

    The overall average blood sugar was almost exactly the same.

    I suspect lipids are similar.

    I once tested my triglyceride levels every hour all day on a low-carb and a low-fat diet.

    You can see the results graphed in the second edition of my book "The First Year: Type 2 Diabetes."

    On the low-fat diet, at first the TGs went down, but then they started to climb and by the end of the day they were higher than they had been when I started.

    Of course with a home meter I couldn't differentiate different types of TG.

    I had been eating LC, so I was adapted to that way of eating. I didn't eat low-fat for a week before doing the low-fat trial, so those results might be questionable.

  • UofMWolverine81

    11/11/2009 1:34:37 AM |

    How much of an impact does/do you suspect that the quality of food choice have/has on this "stacking effect"?

    Is this much of an issue for someone eating every 3-4 hours or so and consuming lean meats, fresh fruits and vegetables, moderate amounts of fat from avocados, coconut, olives, nuts/seeds, and so on?

    The offerings in the study, while possibly common fair for many folks, is hardly indicative of what a lot of health-conscious fitness types are doing these days, which is why I ask.

    I'm curious if the same issue would still exist with more health-promoting choices, even if to a smaller degree, or if it is not an issue in that case.

  • Dr. William Davis

    11/11/2009 2:00:01 AM |

    A clarification: The meal used in this study was not intended to represent some sort of "ideal" meal, but a meal of exaggerated composition that yields useful observations during the testing period. I would not interpret the data to suggest that the diet was good nor bad. (Though, obviously, thes were junk food meals.)

    Both fats and carbohydrates affect postprandial patterns in complex ways. Recall, for instance, that fructose causes extravagant distortions of postprandial responses.

  • shel

    11/11/2009 2:16:43 AM |

    perhaps this makes the case for eating (a) high fat, moderate protein meal(s) during the day.

    my breakfast consists of fat/meat and lunch is olive oil/bison sashimi or olive oil/lamb sashimi, both with fresh herbs. not much in the way of carbs. i don't know yet, but i have doubts about the negative effects of chylomicrons in the absence of carbs.

  • Anonymous

    11/11/2009 2:34:43 AM |

    But would the 9-hr pattern really be
    better if they had the same total intake all in one meal? This is not shown.
    Presumably it'd have only one peak, but that peak would be significantly higher.

  • Sifter

    11/11/2009 3:55:32 AM |

    This contrarian study of low carb linked with atherosclerosis in mice...does raise some questions on high protein/low carb effect on endothelium (edited to fit space)

    A new study reported Online in the Proceedings of the National Academy of Science (August 24, 2009) provides information about the effect of the low-carb, high-protein diet on the health of blood vessels.

    Conducted by a team of scientists at Beth Israel Deaconess Medical Center (BIDMC), the study found that mice placed on a 12-week low-carb, high-protein diet showed a significant increase in atherosclerosis—and an impaired ability to restore blood vessels.  

    Senior author Anthony Rosenzweig, MD, Director of Cardiovascular Research at BIDMC and Professor of Medicine at Harvard Medical School, and lead author Shi Yin Foo, MD, a clinical cardiologist in the Rosenzweig laboratory at BIDMC, conceived the mouse study in a very human manner.

    Dr. Foo began thinking about the possible dangers of low-carb, high-fat diets after seeing heart-attack patients who were on the diet—and after Rosenzweig himself went on the diet.

    “I asked Shi Yin to do a mouse experiment—so we could know what happens in the blood vessels and so I could eat in peace.”

    The doctors fed mice known to develop atherosclerosis in the same manner as humans one of three diets: a standard mouse diet (65% carbs, 15% fat, 20% protein), a “Western diet” in line with the average human diet (43% carbs, 42% fat, 15% protein), and low-carb, high-protein diet (12% carbs, 43% fat, 45% protein). All three diets contained the same amount of calories. The last two diets contained the same amount of fat and cholesterol.

    As in most such diets, carbs were replaced with protein.

    Significantly, the low-carb mice exhibited a greater degree of atherosclerosis, as measured by plaque accumulation: 15.3% compared to 8.8% for the Western diet group. “Our question was, ‘Why do the low-carb mice have such an increase in atherosclerosis,’” Foo said.

    Importantly, traditional markers slightly favored the low-carb group. “None of these results explained why the animals’ blood had more atherosclerotic blockages and looked so bad,” Foo said.  

    The researchers looked at the animals’ endothelial or vascular progenitor cell (EPC) counts. “Examination of the animals’ bone marrow and peripheral blood showed that the measures of EPC cells dropped fully 40% among the mice on the low-carb diet—after only two weeks,” Rosenzweig said.

    This finding suggests that the low-carb, high-protein led to an impaired ability to form new blood vessels in tissues deprived of blood flow, as occurs with atherosclerosis. The researchers hypothesized that the Western diet and the low-carb/high-protein diet caused “comparable injury and inflammation.” The low-carb group, however, suffered an impaired ability to repair and restore blood vessel function.

    Rosenzweig  continued: “Although the precise nature and roll of [EPC] cells is still being worked out, these results succeeded in getting me off the low-carb diet.”

    Rosenzweig stressed the apparent disconnect between weight loss and standard blood markers—where the low-carb diet worked—and vascular health. It appears that blood vessel health can be affected by more than fat and cholesterol—in this case, carbs and protein.  

    Protein—the bodybuilder’s favorite macronutrient—may actually be an offender. Too much protein (and too little carbohydrate) may damage blood vessels and/or prevent restoration.

    “For now,” says Rosenzweig, “it appears that a moderate and balanced diet, coupled with exercise, is probably best for most people.”

  • David

    11/11/2009 5:12:36 AM |

    Sifter, that study was kind of ridiculous. They used ApoE-/- mice. Read Peter's enlightening take on it here:

    And Part II:

  • Felix

    11/11/2009 9:03:14 AM |

    I tend to eat every three hours, five meals a day. My triglycerides were recently meausred, they're at 33. I guess that does not support your bet, right? Or maybe I am getting this all wrong...
    Kind regards,

  • Peter

    11/11/2009 12:43:13 PM |

    Ornish advocates grazing and scored zero on the heart scan, so maybe what you eat is more critical than when, for plaque building.  He, like you, wouldn't go near the refined carbs in the experiment you cite.

  • Dr. William Davis

    11/11/2009 1:05:15 PM |

    When you see the patterns in hundreds or thousands of people, you realize that not everybody is the same. In fact, the range of differing responses is dramatic.

    So, no, you cannot draw any conclusions about the experience of one.

  • Beth

    11/12/2009 6:28:40 PM |

    I must be missing something, but wouldn't eating smaller meals result in smaller peaks and possibly quicker decline? So yes, stacking may occur, but isn't it conceivable that overall blood levels would be no higher than they would be with the larger meals?

  • Jim Purdy

    11/12/2009 11:45:31 PM |

    I agree with Beth.

  • Anonymous

    11/13/2009 2:23:16 AM |

    Beth, Jim,

    That's the question I alluded to above
    (see above, between Shel's & Sifter's

    We would really need to see the corresponding curve for the same subjects, instructed to eat both meals
    at one go.

    So it doesn't look like this study by itself allows us to draw definite conclusions (on the question of grazing vs. gorging).

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  • Isaac

    3/25/2010 2:04:30 PM |

    This just reinforces the notion that fasting triglyceride levels are fairly useless for predicting disease.  It's the postprandial that matters since most people spend most of their lives in a postprandial state.

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