Diwali marks the onset of winter and North Indian delicacies like Chole Bhature, Kulche, Lassi and food items with a lot of ghee are too heavy to digest in summers and monsoons but make perfect winter foods. Usually, people complain of digestion problems when they are high on fat in summer and monsoon.
Pre-winter is from mid-November to mid-January which is Hemant Ritu as per the Indian calendar and the winter is from mid-January to mid-March which is Shishir Ritu. It is a cooler time of the year, as it's Dakshinayan (winter solstice) - a phase where the moon's influence on earth is much stronger.
It is a season marked by vata - kapha in the environment and in the body. To keep up with the external cold (vata) - agni i.e. the body's digestive fire is at its peak in the winter season so the body can acclimatise with the cold weather.
For people who have a hard time gaining weight, this is the best time as the Kapha in the body is high during winter. So winters are the time when you can eat foods you usually love but cannot digest in other seasons due to the heavy nature of food - like sweets, high-protein foods, etc. During this season, it is cold and windy. So, heavy foods provide warmth and stability to the body.
Winters are also the best time to scale up your workout and physical activities because the body can naturally build strength because it can digest and assimilate foods better. The sun sets earlier and rises late so the body goes into rest and relax mode more easily.
Since it's natural for the body to rest, it gets easier for the body tissues to be nourished. Winters happen to be the best season for sunbathing too.
Asanas and Pranayamas which are generally not advisable when it's hot can be done in this season.
Asanas like Suryanamaskar, Pranayam like Bhastrika and Shuddhikriyas like Kapalbhati can be practised vigorously during this season. Traditionally, in India, it's the best time to train for wrestling.
It is advisable to apply warm oils so as to protect the body from cold winds, and exfoliation. Dry masks are to be avoided by all means due to the increased dryness due to cold. Likewise, cold foods, cold water and raw foods are best avoided.
Since it's a time when the body may get a bit more prone to cold and sluggishness due to an increase in Kapha, it is the time to enjoy the warm water, hot tea and coffee.
Burning medicated incense sticks helps clear the respiratory passage of excess mucus. Fasting and dieting should be avoided in this season because when the body craves food, it uses its own tissues as fuel for that extra hunger.