OK, let's try to identify all the variables.
The food we eat is used by our bodies, or it acts as fodder for various intestinal microbes. I'm going to write a table with three columns - John's ability to absorb the food, the effect it has on the "good guys" (friendly bacteria), and the effect it has on the "bad guys", the microbes that produce butyric acid and neuro toxins etc. This is not hard science; mostly educated speculation. And it's not all or nothing either. He can drink some juice and absorb it, but if he drinks too much at one sitting, the excess feeds the bad guys, and we're in trouble. I will use the term "excess", in the third column, to indicate this. I may also use the term "with meals" in the first column, because he can absorb more carbs if they are eaten with a meal. The food slows everything down, and gives him time to absorb the sugar, before it reaches his intestines. I'll provide additional detail below, but first, the table.
| Food | Absorb | Good Guys | Bad Guys |
|---|---|---|---|
| Protein | ok | ||
| Fats/Oils | ok | ||
| Fruit | ok | ||
| Juice | 6oz with food | excess | |
| Sucrose | trace | all | |
| Maltose/Dextrins | trace | all | |
| Lactose | 8oz with food | 8oz | excess |
| Starch | 10carbs with food | excess | |
| Fiber | 2g per meal | excess | |
| Oligos | 1g per meal | excess | |
| Sugartols | 1g with food | excess | |
| Sacharin | |||
| Nutrasweet | 1 diet drink per day | ? | |
| Sucralose | ? | ||
| MSG et al | ? |
My observations agree with the SCD guidelines; proteins and oils are safe. Yet this seems a bit odd. If you leave a piece of steak on the counter for days, it will rot. Bacteria can live on almost anything. So why don't the bad guys take advantage of the excess lipids and amino acids in his meals? Perhaps the bacteria that thrive on protein don't do well in an anaerobic environment. Perhaps John's lipases and proteases are just fine, while his carb enzymes are mal-shaped in some way. I don't know; I can't explain it. But for now, meat and oil seem to be quite safe.
Fruits are safe too, and pure fruit juice in moderation. This is new with the specific carbohydrate dyet, and a far cry from the anticandida diets of the 70's and 80's. Yes, I've seen John eat two or even three bananas within a couple hours, on an empty stomach, and nothing happened. He seems to absorb the monosaccharids, just like the book says. Juice is not "free", but a little bit with meals seems to be ok.
Sucrose, as in cane sugar, molasses, corn syrup, maple syrup, etc, is definitely the worst. He can handle the sucrose that occurs naturally in fruits and veggies, but don't add any refined sugars into the mix. None.
Maltose is rare, although maltodextrins are added to a lot of processed foods. He doesn't seem to absorb these well, so try to avoid them.
Lactose is the only item on the chart that helps the good guys. He's been drinking a small carton of milk at lunch, and I may start giving him 4oz with dinner. Bear in mind, the SCD says no milk. They prescribe homemade goat yogert. No doubt that would be superior, but I don't think Wendy and I are ready to start making homemade goat yogert, and John wouldn't eat it in any case, so milk will have to do.
I don't know what to say about starch, because he has had some good days after eating modest amounts of rice or potato. But he's had some really really bad days after large starchy meals, and I could smell the butyric acid. I'm setting an upper limit of 10 grams of starch as part of a larger meal, though this is only a guess. He can handle a couple of fries, or a thin bed of rice or rice noodles. No more than that.
The SCD says nothing about oligosaccharids or fiber/cellulose, and that really surprises me. These are 100% undigestable by humans. (Absorb column is blank for these items.) That's why beans give us gas; the bacteria eat the oligos and produce methane and carbon diaoxide. So - do these undigestable sugars feed the good guys or the bad guys? I think a small amount can help, but John definitely reacts to large servings of green beans or broccoli. Don't serve more than a couple grams of oligos and/or fiber with any meal.
Sugar alcohols, like sorbitol and manitol, are absorbed slowly. That's good if you're a diabetic - no insulin spike - but if you're John, it gives the bad guys time to multiply. We usually avoid these, although sometimes a trace of sorbitol in ursatz maple syrup is better than a boat load of sucrose in true maple syrup. You have to pick your poison.
We really don't know about the artificial sweeteners. Sacharin is the safest, but hard to find. I think Nutrasweet is ok in moderation. SCD says sucralose and stevia are really bad (bacteria eat those).
Other artificials are also uncertain. We believe he reacts to MSG. This doesn't feed the bacteria; it's just something he reacts to. The standard food colorings and preservatives seem to be ok, but don't push it.