Decoding the afternoon drowsiness

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A study published in the Journal of Applied Physiology in 1998, reported that postprandial increases in sleepiness were apparent at a wide range of times during a typical 9-to-5 working day, although the extent of the postprandial sleepiness was greatest after meals eaten between 11 am and 2 pm.

What causes food coma? Food should not make us feel fatigued, in fact it should be the opposite, that is, we should feel energised. Increased sleepiness is thought to be caused by hormonal and neuro-chemical changes related to both quantity and type of food. The key is obviously in how much we eat and what we eat.

Some foods improve energy levels, while others may hinder it. Overeating results in foggy feeling and sluggishness. Food coma is often triggered by big meals and high carbohydrate and fat rich meals. The bigger the meal, the easier it gets to slip into food coma. Many scientific studies have also indicated that sleepiness increases after meals and that the extent varies according to the fat and carbohydrate content of the food eaten.

High carbohydrate and high glycemic index foods like rice, bread, cakes, cookies, sweets, desserts, fruit juices can cause fluctuations in blood sugar levels. High glycemic foods rapidly break down into glucose, the simplest form of sugar in our body, causing a spike in blood sugar levels. This is followed by a spike in insulin levels (the hormone secreted by the pancreas) to bring down blood sugar levels as quickly. The rapid rise in insulin also causes our brain to produce a neuro-transmitter like serotonin and melatonin that leave us feel drowsy and sleepy. Wider fluctuations in blood sugar levels increase the fatigue and lethargy. So, it’s no surprise that high carbohydrate eating communities of the world like the Italians and those in eastern India declare siesta time and officially shut-shop for a few hours post lunch!

Food coma can also come independent of the composition of the meal, if the meal is large. The response to a larger quantity or volume in the digestive tract triggers a response to the nervous system to induce sleepiness.

Author is a clinical nutritionist and founder of http://www.theweightmonitor.com and Whole Foods India