Posted on by Joy Erdile, MSc, RD

When to Eat and Not Eat, How Many Meals and Snacks

Introduction

Historically, “when we eat” was a non-issue; we ate when it was daylight and food was available, and we fasted when it was dark. With modern lighting and refrigeration, our “day” lasts as long as the lights are on, and food is available around the clock. To understand the current science of meal timing, we must look at the history of the three-meal-per-day standard and the rise of snacking.

A Brief History of Meals and Snacks

In the Middle Ages, daylight dictated meal times, with lunch being the main event of the day. Breakfast became popularized in the mid-19th century for laborers and was later marketed heavily by the cereal industry. Snacks were once frowned upon as unhygienic, only becoming a staple in the 1950s due to the rise of processed food manufacturing [1,2]. Between 1977 and 2006, daily caloric intake rose by approximately 570 calories, largely due to snacking [3].

The “Vicious Cycle” of Type 2 Diabetes Treatment

Before insulin, diabetes was managed by strictly restricting carbohydrates. Experts like Dr. William Osler recommended a diet of 65% fat and only 3% carbohydrate [4]. Today, many patients with type 2 diabetes enter a vicious cycle: high carbohydrate intake leads to higher insulin doses, which drives weight gain and increases insulin resistance, further increasing cardiovascular risk [8].

Challenging the “Snacking” Dogma

Since 2009, many have been advised to eat six times a day to “manage” blood sugar. However, a 2019 study in Diabetes Care found that patients who ate three meals per day (without snacks) saw significantly better results than those eating six times, even with the same total calories. The three-meal group lost an average of 12 pounds more and reduced their HbA1C by 1.2% in just 12 weeks [8].

Chronobiology and Circadian Rhythms

Our bodies are governed by circadian rhythms—internal clocks optimized for eating during daylight and fasting at night [16,17]. Blood sugar control fluctuates according to these rhythms; identical foods eaten in the evening cause much higher spikes than when eaten in the morning [18-20]. This suggests that carbohydrate sources are best consumed at breakfast.

When Not to Eat: Intermittent Fasting

While intermittent fasting is popular, timing matters. Fasting until noon has been shown to trigger higher blood sugar spikes after lunch and dinner in those with type 2 diabetes [21]. Aligning your “eating window” with your body’s natural clock is essential for appetite control and glucose regulation.

More Info?

If you would like me to design a Meal Plan for you that aligns your eating times with your natural circadian rhythms, you can learn about me and the Comprehensive Dietary Package that I offer.

To your good health!

Joy

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References

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  2. Carroll A. How Snacking Became Respectable. The Wall Street Journal. Published August 30, 2013. [https://www.wsj.com/articles/how-snacking-became-respectable-1377906874]
  3. Duffey KJ, Popkin BM. Energy Density, Portion Size, and Eating Occasions: Contributions to Increased Energy Intake in the United States, 1977–2006. PLOS Medicine. 2011;8(6):e1001050. [https://doi.org/10.1371/journal.pmed.1001050]
  4. Osler W. The Principles and Practice of Medicine. New York, NY: D. Appleton and Company; 1892. [Archival Source]
  5. Woodyatt RT. Bernhard Naunyn. Diabetes. 1952;1(3):240–241. [https://pubmed.ncbi.nlm.nih.gov/14936838/]
  6. Allen FM. Studies Concerning Diabetes. JAMA. 1914;LXIII(11):939–943. [https://doi.org/10.1001/jama.1914.02570110041011]
  7. Joslin EP. The Treatment of Diabetes Mellitus. 2nd ed. Philadelphia, PA: Lea & Febiger; 1917. [Archival Source]
  8. Jakubowicz D, Landau Z, Tsameret S, et al. Reduction in Glycated Hemoglobin and Daily Insulin Dose Alongside Circadian Clock Upregulation in Patients With Type 2 Diabetes Consuming a Three-Meal Diet: A Randomized Clinical Trial. Diabetes Care. 2019;42(12):2171–2180. [https://doi.org/10.2337/dc19-1142]
  9. Seagle HM, Strain GW, Makris A, Reeves RS. Position of the American Dietetic Association: Weight Management. Journal of the American Dietetic Association. 2009;109(2):330–346. [https://doi.org/10.1016/j.jada.2008.11.033]
  10. Canadian Diabetes Association. Beyond the Basics: Meal Planning for Healthy Eating, Diabetes Prevention and Management. Toronto, ON: Canadian Diabetes Association; 2014. [Clinical Guideline: https://www.rvh.on.ca/wp-content/uploads/2023/07/Beyond-the-Basics-PDF.pdf]
  11. Arnold L, Mann JI, Ball MJ. Metabolic effects of alterations in meal frequency in type 2 diabetes. Diabetes Care. 1997;20(11):1651–1654. [https://doi.org/10.2337/diacare.20.11.1651]
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  14. Dyar KA, Ciciliot S, Wright LE, et al. Muscle insulin sensitivity and glucose metabolism are controlled by the intrinsic muscle clock. Molecular Metabolism. 2014;3(1):29–41. [https://doi.org/10.1016/j.molmet.2013.10.005]
  15. Sadacca LA, Lamia KA, deLemos AS, Blum B, Weitz CJ. An intrinsic circadian clock of the pancreas is required for normal insulin release and glucose homeostasis in mice. Diabetologia. 2011;54(1):120–124. [https://doi.org/10.1007/s00125-010-1921-1]
  16. Poggiogalle E, Jamshed H, Peterson CM. Circadian regulation of glucose, lipid, and energy metabolism in humans. Metabolism. 2018;84:11–27. [https://doi.org/10.1016/j.metabol.2017.11.017]
  17. Saad A, Dalla Man C, Nandy DK, et al. Diurnal Pattern to Insulin Secretion and Insulin Action in Healthy Individuals. Diabetes. 2012;61(10):2691–2700. [https://doi.org/10.2337/db11-1478]
  18. Bo S, Fadda M, Castiglione A, et al. Is the timing of caloric intake associated with variation in diet-induced thermogenesis and in the metabolic pattern? A randomized cross-over study. International Journal of Obesity. 2015;39(12):1689–1695. [https://doi.org/10.1038/ijo.2015.138]
  19. Jakubowicz D, Barnea M, Wainstein J, Froy O. High Caloric intake at breakfast vs. dinner differentially influences weight loss of overweight and obese women. Obesity. 2013;21(12):2504–2512. [https://doi.org/10.1002/oby.20460]
  20. Morgan LM, Shi JW, Hampton SM, Frost G. Effect of meal timing and glycaemic index on glucose control and insulin secretion in healthy volunteers. British Journal of Nutrition. 2012;108(7):1286–1291. [https://doi.org/10.1017/S000711451100618X]
  21. Jakubowicz D, Wainstein J, Ahren B, Landau Z, Bar-Dayan Y, Froy O. Fasting Until Noon Triggers Increased Postprandial Hyperglycemia and Impaired Insulin Response After Lunch and Dinner in Individuals With Type 2 Diabetes: A randomized clinical trial. Diabetes Care. 2015;38(10):1820–1826. [https://doi.org/10.2337/dc15-0761]
 
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