Holiday Hacks and Hints Part One: The Holiday Effect

Did you know that there are more heart attacks during the December holiday season than at any other time of the year?  It has been observed that, on a day-to-day basis, heart-related deaths are 4.7% higher from December 5th to January 7th each year.  Additionally, within this time there are two peaks in heart attacks, the first falls on December 25th and the day after and the second on January 1st (1).  On a yearly basis there are 33% more coronary artery-related deaths in December and January than in June through September (2).  It was once believed that cold weather was the major causative factor for these occurrences but this idea was laid to rest by a study from New Zealand.  In the southern hemisphere where New Zealand is located, the rate of death from natural causes is generally lower during the summer season. However, the Christmas and New Year celebrations fall within this warm season and so does the spike in heart-related deaths, the same increase that appears in the northern hemisphere during the cold season (3).  In addition, research reveals that the average age of these holiday-associated deaths is younger by almost a year than similar deaths during the rest of the year (3).

There are many possible reasons for this phenomenon. Emotional stress associated with the holidays; delay in seeking medical care because of travel and visiting obligations; “death displacement” or the ability of people to postpone death until they have had one last visit with family and friends are some of these.  But there is another potential culprit that may be playing a major role here.  That is the almost inevitable change in dietary intake during the holiday season, a time of year that is celebrated by indulging in more treats and meats that add extra fat and sugar to a normally more balanced diet.

Let’s look at the immediate effects of holiday food extravagance on the human body.  The following is based on an excellent chart prepared by the PCRM (Physicians Committee for Responsible Medicine) which summarizes the alarming consequences of eating a SINGLE HIGH-FAT MEAL (4);


Immediately after eating a high fat meal…

Triglycerides rise. (Triglycerides are a type of fat found in the bloodstream.) (5,6).

Cholesterol increases, contributing to the formation of plaques within blood vessels (4).

Factors that promote the clotting of blood are activated (7,8).


 One hour later…

Endotoxins increase by almost three times after a meal high in saturated fat. Endotoxins are damaging substances present inside bacteria cells that are released when the bacteria disintegrate.  Meals including vegetable and fish oils do not cause this increase. These endotoxins promote the growth of plaques in arteries (9,10,11).


 Two hours later…

Triglycerides are now increased by 60% (5,6).

Blood flow through the arteries has been cut in half (12).

The heart is beating harder and blood pressure has risen (13).

Antioxidant enzymes in the blood are depleted (6).

Testosterone levels in healthy men drop significantly after eating a high-saturated-fat meal (14).


Three hours later…

Blood vessel function has become abnormal (12).

The lining of the arteries (endothelium) has lost elasticity and blood flow is continuing to slow down (5,6,15).  Oils sourced from both plants and animals exhibit similar damaging effects to the endothelium (24).


Four hours later…

The blood has thickened and is now flowing even more slowly than it was 2 hours ago.   Blood actually becomes “milky” with fat (5).

Production of cholesterol-rich particles such as VLDL (very low density lipoproteins) and chylomicrons is increased.  These particles increase plaques in artery walls and can raise the risk of a coronary heart disease event such as a heart attack nearly three-fold (16,17).


Five hours later…

Triglycerides have now increased by 150% (5,6).


Six hours later…

The usual beneficial anti-inflammatory effect of high-density cholesterol (HDL – the “good cholesterol”) is compromised so that plaque production in artery walls actually increases (12).

A meal high in saturated fat reduces insulin sensitivity for hours and drives fatty lipids to be stored in the liver (9,18,19).


And what if the consumption of high-fat foods continues over days, weeks, months…

Plaque in the arteries continues to build up, further reducing blood flow and decreasing oxygen supply to the heart, the trigger for a heart attack (5,6,9,13,20) .

Conditions are prime for the development of non-alcoholic fatty liver disease (21).


These effects occur in both healthy and unhealthy people. 

In people who already have heart disease and less than optimal blood flow to the heart

one fatty meal can be fatal  

This is the “holiday effect”


In addition, a fatty meal can cause angina (chest pain that originates from the heart) in a person with cardiovascular disease, even if they are sitting or lying down. This phenomenon was first observed more than 200 years ago and was illustrated scientifically in 1955 after researchers had their subjects drink high-fat heavy cream (40% butterfat) (22).  No angina pain occurred after ingestion of a low-fat meal.



This new investigation adds to our already considerable knowledge of the deleterious effect of high fat foods.  In this study a single high-fat drink caused dramatic and almost immediate changes in the blood cells and blood vessels of healthy, physically fit men.  Half the men in this study drank a very-high-fat milkshake of 1000 calories and 80 grams of fat (consisting of whole milk, heavy whipping cream and ice cream) and the other half ate a low-fat meal with the same number of calories but very little fat (consisting of three large bowls of sugar-coated flakes with no-fat milk).


The researchers focused on the effects of the high-fat food on blood cells and many detrimental changes were observed.

Blood flow was significantly reduced.

Plasma (the fluid portion of the blood) was thick, pink and filled with fat, dramatically unlike its usual clear yellowish appearance.

The content of fats in the blood in the form of total cholesterol, triglycerides and free fatty acids was significantly increased.

The presence of reactive oxygen species in the blood was increased.  These are associated with inflammation.

An enzyme called myeloperoxidase (MPO) was increased.  This enzyme is linked to loss of elasticity in blood vessels and destabilization of plaques in blood vessels, both of which can result in a heart attack or stroke.

Red blood cells were smaller and their normally smooth surface was prickly with projections making them more likely to clump together to form clots, potentially destabilizing atherosclerotic plaques and leading to heart attacks.

White blood cells were bloated with fat absorbed from the excessive amount of fat in the bloodstream.  These “foamy monocytes” raise inflammation and add to plaque formation.


 The low-fat meal produced none of these effects (23).


Researchers observed that the harmful changes in these robust, athletic men were evident four hours after the high-fat drink and mostly disappeared after eight hours.  Indeed, a healthy human body is able to tolerate one extra-fatty meal and recover from its effects.  But there is a cumulative toll taken by the habitual eating of high-fat food and many people eating a standard Western diet are inadvertently delivering three high-fat blows to their body every day.  Happily, it is almost never too late to alter your trajectory.  This holiday season might be a good time to steer away from traditional festive foods rich in fats and sugar and look into the bounty of delicious treats that are made without adding ingredients that challenge your long-term health and well-being.



 1  Phillips, D.P., Jarvinen, J.R., Abramson, I.S., Phillips, R.R. Cardiac mortality is higher around Christmas and New Year’s than at any other time the holidays as a risk factor for death. Circulation. 2004; 110: 3781–3788.

2  Kloner, R.A., Poole, W.K., Perritt, R.L. When throughout the year is coronary death most likely to occur? A 12‐year population‐based analysis of more than 220 000 cases. Circulation. 1999; 100:1630–1634.

3 Knight, J., Schilling,C., Barnett, A., Jackson, R., Clarke, P.  Revisiting the “Christmas Holiday Effect” in the Southern Hemisphere.  J Am Heart Assoc. 2016 Dec; 5(12): e005098. Published online 2016 Dec 22. doi:  [10.1161/JAHA.116.005098]

5  Vogel, R.A., Corretti, M.C., Plotnick, G.D.  Effect of a single high-fat meal on endothelial function in healthy subjects.  Am J Cardiol. 1997 Feb 1; 79(3):350-4.

6  Tsai, W.C., Li, Y.H., Lin,C.C., Chao, T.H., Chen, J.H.  Effects of oxidative stress on endothelial function after a high-fat meal.  Clin Sci (Lond). 2004 Mar; 106(3): 315-319.

7  Delgado-Lista, J., Lopez-Miranda, J., Cortés, B., Perez-Martinez, P., Lozano, A., Gomez-Luna, R., Gomez, P., Gomez, M.J., Criado, J., Fuentes, F., Perez-Jimenez, F.  Chronic dietary fat intake modifies the postprandial response of hemostatic markers to a single fatty test meal.  Am J Clin Nutr. 2008 Feb; 87(2): 317-322.

8  Freese R1, Mutanen M.  Postprandial changes in platelet function and coagulation factors after high-fat meals with different fatty acid compositions.  Eur J Clin Nutr. 1995 Sep; 49(9):658-664.

9  Anderson, A.S., Haynie, K.R., McMillan, R.P., et al. Early skeletal muscle adaptations to short-term high-fat diet in humans before changes in insulin sensitivity. Obesity. 2015; 23: 720-724.

10  Lyte, J.M., Gabler, N.K., Hollis, J.H.  Postprandial serum endotoxin in healthy humans is modulated by dietary fat in a randomized, controlled, cross-over study.  Lipids Health Dis. 2016 Nov 5; 15(1):186.

11  Erridge, C., Attina, T., Spickett, C.M., Webb, D.J.   A high-fat meal induces low-grade endotoxemia: evidence of a novel mechanism of postprandial inflammation.  Am J Clin Nutr. 2007 Nov; 86(5):1286-92.

12  Nicholls, S.J., Lundman, P., Harmer, J., et al. Consumption of saturated fat impairs the anti-inflammatory properties of high-density lipoproteins and endothelial function.   J Am Coll Cardiol. 2006; 48: 715-720.

13  Jakulj, F., Zernicke, K., Bacon, S.L., Wielingen, L., et al. A High-Fat Meal Increases Cardiovascular Reactivity to Psychological Stress in Healthy Young Adults. J Nutr. 2007; 137:935-939.

14  Meikle, A.W., Stringham, J.D., Woodward, M.G., Mcmurry, M.P.  Effects of a fat-containing meal on sex hormones in men.  Metabolism Sep 1990; 39(9):  943-946.

15 Tentolouris N1, Arapostathi C, Perrea D, Kyriaki D, Revenas C, Katsilambros N.  Differential effects of two isoenergetic meals rich in saturated or monounsaturated fat on endothelial function in subjects with type 2 diabetes.  Diabetes Care. 2008 Dec; 31(12):2276-2278.

16  Varbo, A., Benn, M., Tybjærg-Hansen, A., Jørgensen, A.B., Frikke-Schmidt, R., Nordestgaard, B.G.  Remnant Cholesterol as a Causal Risk Factor for Ischemic Heart Disease.  J Am Coll Cardio Jan 2013; 61(4):                                       DOI: 10.1016/j.jacc.2012.08.1026

17  Rifai, N., Merrill, J.R., Holly, R.G.  Postprandial effect of a high fat meal on plasma lipid, lipoprotein cholesterol and apolipoprotein measurements. Ann Clin Biochem. 1990 Sep; 27 ( Pt 5):489-493.

18  Hernández, E.Á., Kahl, S., Seelig, A., Begovatz, P., Irmler, M., Kupriyanova, Y., Nowotny, B., Nowotny, P., Herder, C., Barosa, C., Carvalho, F., Rozman, J., Neschen, S., Jones, J.G., Beckers, J., de Angelis, M.H., Roden, M.  Acute dietary fat intake initiates alterations in energy metabolism and insulin resistance.  J Clin Invest. 2017 Feb 1; 127(2):695-708.

19  Robertson, M.D., Jackson, K.G., Fielding, B.A., Williams, C.M., Frayn, K.N.  Acute effects of meal fatty acid composition on insulin sensitivity in healthy post-menopausal women.  Br J Nutr. 2002 Dec; 88(6): 635-40.

20  Anderson, R.A., Jones, C.L., Goodfellow, J.  Is the fatty meal a trigger for acute coronary syndromes.  Atherosclerosis. 2001 Nov; 159(1):9-15.


22  Kuo, K.U., Joyner, C.R.  Angina pectoris induced by fat ingestion in patients with coronary artery disease; ballistocardiographic and electrocardiographic findings.  J Am Med Assoc. 1955 Jul 23; 158(12):1008-1013.

23  Benson, T.W., Weintraub, N.L., Kim, H.W., Seigler, N., Kumar, S., Pye, J., Horimatsu, T., Pellenberg, R., Stepp, D.W., Lucas, R., Bogdanov, V.Y., Litwin, S.E., Brittain, J.E., Harris, R.A.  A single high-fat meal provokes pathological erythrocyte remodeling and increases myeloperoxidase levels: implications for acute coronary syndrome.  Lab Invest. 2018 Oct; 98(10):1300-1310.

24  Rueda-Clausen, C.F., Silva, F.A., Lindarte, M.A., Villa-Roel, C., Gomez, E., Gutierrez, R., Cure-Cure, C., López-Jaramillo, P.  Olive, soybean and palm oils intake have a similar acute detrimental effect over the endothelial function in healthy young subjects.  Nutr Metab Cardiovasc Dis. 2007 Jan; 17(1):50-57.







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My name is Debra Harley (BScPhm) and I welcome you to my retirement project, this website. Over the course of a life many lessons are learned, altering deeply-rooted ideas and creating new passions.

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