Milk and yogurt in a low GI diet
Reduced or low fat or skim dairy and soy milk and yogurt are handy foods to have on hand for healthy drinks or snacks that can lower the overall GI of your diet.
Milk’s low GI (20–34 for various skim to regular fat cow milks) is a combination of its naturally low GI sugar (lactose) plus milk protein, which forms a soft curd in the stomach and slows down the rate of stomach emptying. The unique mix of amino acids in cow milk protein are also thought to stimulate insulin secretion, further lowering the GI. Low fat flavoured milks also have a low GI (26–42). Yes, they have added sugar, but it’s in relatively modest amounts (about 4%) compared with soft drinks (11–12%). Some are also made with alternative sweeteners. We don’t have GI values for goat milk as it hasn’t been tested (nor has camel milk). However, they are likely to be similar to cow milk.
Soy milk is dairy- and lactose-free and an easy way to include soy protein in your diet. The GI values of soy milks range from 16–45. To ensure it is a suitable alternative to regular dairy milk, manufacturers enrich it with calcium, riboflavin and vitamin B12.
Oat milk’s GI value (69) is roughly twice that of dairy milk, however we think it’s probably a better option than rice milk (GI 79–92) if you are choosing a grain-based milk. Look for calcium-enriched products. The only GI-tested almond milk to date is Almond Breeze (GI 25 for Almond Breeze Original). It’s not a significant source of protein or carbs (1g and 2g respectively in 240ml serving). We reported on it in GI News HERE. Rice milks that have been tested to date have very high GI values (Australia’s Own GI 92 and Vitasoy GI 79). They are typically processed from brown rice and are essentially a source of carbs (24g per cup). Choose calcium-enriched products if you buy them.
Yogurt’s low GI values are thanks (mainly) to the combination of acidity and high protein and of course the fact that lactose, the sugar in milk, has a naturally low GI (46). How low does yogurt go? Well, testing at the University of Sydney has found ‘diet’ yogurts have the lowest GI values (14–21) and contain fewer kilojoules/calories, and around half the carbohydrate compared with yogurts that have added sugars (26–43). Even if you are lactose intolerant, you can enjoy yogurt without symptoms because the ‘bugs’ (i.e. culture organisms added to milk to make yogurt) do the job of lactase digestion for you.
Soy yogurt (GI 50) is usually made from soybeans or soy protein rather than soy drink. Look for calcium-enriched, low fat varieties.