A recent blogpost at Optimising Nutrition pointed out that it's difficult for some people to get enough fiber on low-carbohydrate diets. Many people do well on very low carb diets without added fiber, but some do not.
I thought it would be relevant to point out that the Four Corners Diet, previously the GO Diet, was designed to emphasize fiber as well as monounsaturated fats and low carbohydrate levels. The original name of the diet stems from the names of the two physicians who worked it out, Jack Goldberg and Karen O'Mara. They tried it on a small group of patients, with good results.
Back in the early part of this century, I felt the diet was the healthiest one out there for people with type 2 diabetes, so I worked with them to add some comments about the beneficial effect of the diet for type 2, and it was published as the Four Corners Diet, emphasizing low-carb, high-fiber, high-mono fat, and what we called pharmafoods, foods with health benefits beyond their macronutrients. These include fermented foods like yogurt or kefir as well as foods containing antioxidants, cancer-inhibiting compounds, phytoestrogens, and cholesterol reducers.
Goldberg was the first person to point out that yogurt and kefir have less carbohydrate than the milk from which they're made, and he even tested the carb count in yogurt and showed that you can subtract 1 gram of carb for every ounce, so a cup of milk, with about 12 grams of carbs, would result in only 4 grams of carbs in well-fermented yogurt and kefir. (The counts can vary a bit depending on when you stop the fermentation. Sour is best as it has the least amount of carbohydrate.)
Unfortunately, the book was published just as a low-carb trend had peaked and was coming down, so the book did not do well. However, that's a benefit for you, as you can now get a used copy for a penny plus shipping.
I still think the diet is the healthiest out there. And all the suggested menus include nutritional analysis of carbs, fiber, net carbs, and percentage mono fat. The suggested 7-day starting menus work up slowly to a lot of fiber, but by day 7 you'd be getting 28 grams of fiber, close to the recommended minimum unless you're a man under 50 years, in which case the minimum is 38 grams.
So if you want both low-carb and sufficient fiber, it would be worthwhile to look into this book.