Most of the parents convince their kids saying that"drink your milk quickly so that you'll grow big and strong!". Because, milk does provide valuable macronutrients (Protein, Fat &Carbohydrates) as well as micronutrients (Vitamin A, C, D, B Vitamins, Calcium,Iron, Magnesium, Phosphorus, Potassium & Zinc) that kids need during their development. There are so many benefits from drinking milk other than just“strong bones”. Now, the question arises: what milk packet we should pick out of so many variants like full cream, single toned, double-toned, skim milk. 

Looking at these 4 variants, it is very much clear that these variants are differentiated mostly based on Fat%. Before we decide which milk variant will suit kids & which one can be opted by adults, let's compare key nutrients of different variants of milk:

If we look at this chart, Fat is the main nutrient, which is removed from milk to make it single toned, double-toned & skim milk. When low-fat and fat-free variants of milk are prepared, the cream from whole milk is skimmed out. Unfortunately, removing the fat also removes the fat-soluble vitamins (D, A, E and K). As a result, reduced-fat varieties contain lower amounts of many nutrients. However, fortification process of milk ensures that lower-fat milks are nutritionally same as whole milk. 

CONCLUSION: As Fat% reduces, overall calorie content also gets reduces. It means that it is not recommended for children under age 5-6 to give low-fat/skimmed milk, as they need additional calories for brain development as well as overall growth.However, it is a good choice for adults who wish to control their calorie intake for weight loss etc. As skim milk is low in saturated fat, it is recommended in diseases such as heart disease and diabetes.

Note: Nandini milk (majorly supplied in Karnataka) has been considered for different milk variants comparison.