Thanks to innumerable, low-cost electronic devices it has now become easy for us to quantify what we eat. Health apps quickly dispense information over time and content, converting what we have eaten into the most standard measure of energy intake, the calorie. Recommended dietary allowances (RDA) further help us understand if our diet is within acceptable limits. Finally, if we want to lose weight or have a disease, diet plans are created based on our food habits to help achieve certain goals. Numbers, numbers, numbers!
What does our digestive system see? Food in the form of proteins, carbohydrates and lipids. It sees bacteria, micronutrients and chemicals. All along from the tongue to anus, are dotted various receptors to sense what is being consumed and act accordingly. High sugar in the diet? Tweak the glucosidase release and further, insulin release. Too much fat? Free fatty acid receptors in the intestine pick up the signal and convey to the brain to stop eating, acting as satiety signals.
The calorie is a human construct: a standard unit, which is the amount of heat energy required to raise the temperature of 1millilitre (mL) of water at 15oC by 1oC. Does a human stomach operate at 15oC? And is all the food you consume in liquid format? No! This doesn’t take away from the utility of the calorie for it helps to measure how much energy a food item contains. A number to help us in classifying foods and as a logic to make choices. The Indian Council of Medical Research through the National Institute of Nutrition has come up with RDAs for Indians and released an easy to read manual for dietary guidelines. Dietary advice in this manual uses units of grams (g), portion sizes and calories. RDAs is now being revised and NIN is set to release a revised guideline using Estimated Average Requirement and Tolerable Upper Limit for nutrients.
When texts in Ayurveda were compiled the calorie construct had not yet been described. Yet, dietary principles in Ayurveda address how much food we should consume. As a general guideline it advises: “Half of the stomach should be filled with food, one quarter with liquids and another quarter must be kept empty”. Interestingly, the primary focus is on qualitative measures, with reference to the physiology of an individual rather quantitative values. One must decide the quantity of food according to digestive capacity and nature of the food material; rather any kind of fixed values.
Your prakriti, geography, season and body state determine agni, interpreted as digestive capacity, and this should determine quantity and content. Evoking mindfulness, realizing one’s digestive capacity requires introspection, where an individual carefully observe their body, state of digestion and real need for energy. For e.g., Acharyas indicate that, one must restrict the amount to food in dinner that can be entirely digested before ‘Brahmi muhurtham’ (~4 am) of next day or not eat if you don’t feel hunger pangs, or feel that your previous meal is not digested. Further, an ideal portion of meal is that which does not cause discomfort or heaviness in abdomen, obstruction in chest, but gives you satisfaction.
At the gross level, modern and classical advice on diet may appear irreconcilable simply due to quantitative and qualitative approaches. But perhaps if we try to formulate our meals qualitatively first, following Ayurveda and then impose caloric content, we can arrive at a personalised diet? A daily caloric intake, a number, just for ourselves?