I always thought I could not deal with large quantities of milk. So it is occurred I have been refusing to use milk for shakes for a few years already. In 2007 I was introduced with Berardi's nutritional books and before that time I didn't give enough attention to the nutrition part. I noticed that he never mentioned a milk in his books but a plain yougurt instead.
(Can not recall why.)
Since that time I have started doing supershakes based on yougurt (Berardi used water).
As I could not find a plain yogurt I used to buy a yougurt with filing - berries and stuff.
Now I am going to give GOMAD a try and investigating alternatives to milk

I was googling for kefir and yogurt regarding GOMAD and also googled for information regarding Lactore Intolerance.
It was interesting for me that in most cases a yogurt was characterized as thick. But actually
in my country I can choose from two types of yougurt:
--- the one that is no thicker than kefir but without that kefir's acid flavor, it is usually with filling, a plain version can hardly be found
(usually that yougurt is expired after 15/30 days - which considered OK - means it is without preservatives)
--- the one that is very thick in spite of fat content (1%-10%), usually it is imported and expires only after 3 or 6 months - is not recommend due to preservatives, and I have never seen a plain version of it, only with filling.
Locally I can rarely find a kefir with filling and sweeteners. We also have other milk based products like ryazhenka (fermented baked milk) - have not considered it yet as an alternative to milk.
Also I found that both kefir and yougurt do have lactose in them, even a half of a milk lactose content - though they are much easier to digest than a milk.
A typical yogurt (thin and with filling) that I used for supershakes had the following nutritional content:
100g
kcals: 78
fat: 2.5
protein: 2.9
carbs: 10.9
For GOMAD I am planning to use both yougurt and kefir (to dilute yougurt with kefir because former has lots of simple carbs due to filling and it seems not very good for a gut)
I see the problems with a kefir and a yougurt are:
- lower protein content (a little bit)
- lower carbs content (if it is not filled with simple carbs, sweeteners, berries etc. - but what point in milk's carbs if they won't be consumed due to lack of lactose ferment)
- higher calcium content (don't know whether such amount can cause something bad or not)
- lower lysine content - half of a milk (someone mentioned here on forum that lysine was important to raise a calf

)
As of Oct. 7, 2009: 25 yr old, H: 183 cm (6' 0"), BW: 83 kg (183 lbs)
[from 65 kg (143 lbs) since started SL on June 2, 2009]:
Squat: 101 kg, BP: 72.5 kg, DL: 117.5 kg, OHP: 50 kg