Here's what 'The Nude Nutritionist' had to say:
1. Avoid fat-free/skim*: Instead, we recommend less than 4.5g fat/100g serve. Low-fat yoghurt also tends to have a slightly higher protein content because the extracted fat allows for more of the remaining nutrients within the same volume.
2. Reach for Greek/plain varieties: These tend to be the highest in protein and will keep you fuller for longer. Anywhere from 5-10g protein/100g serve is generally a good target.
3. Look for ‘no added sugar’ on packs: As a general guide aim for less than 10g sugar/100g serving for unflavoured/plain yoghurt. If you’re one for the sweetened yoghurts, a drizzle of honey is in no way a deal breaker!
4. Go for probiotics: Natural and Greek yoghurts also tend to be great sources of probiotics – the little bugs that keep your gut happy! Labelling such as “live cultures, acidophilus, lacto bacilli, thermophillus, bifidobacterium” sounds fancy, but all mean probiotics.
5. Compare by 100g if you're buying a large tub. To find the lowest sugar or highest protein option, always compare products by looking at the 100g numbers. If you're buying portion-sized tubs, then you might want to compare using 'per serving'.