Radish is a Green food. Green foods are safe to eat as a regular part of a diet.
Guideline related quotes related to Non-Starchy and Green throughout Geoff Bond's publications.
Eat at least 2 3/4 lbs of mixed salad and vegetables per day, consisting of "Green-Green” and “Green” foods. Of these, at least 3/4 lb should be mixed salad. Also include at least 5 cups of “Green-Green” leafy vegetables or 2 1/2 cups of other vegetables per week. ~Paleo in a Nutshell p.102
Specific references to Radish throughout Geoff Bond's publications.
It is quite easy really to achieve six servings by eating one big salad every day with all the usual ingredients we think of as salad vegetables: Tomatoes, lettuce, radish, cucumber, mushrooms, onions, and so forth. ~Paleo in a Nutshell p.48
Conforming non-starchy, colored plant foods are foods that are low-glycemic, rich in micronutrients and fiber, and harmless with regard to anti-nutrients and antigens. Broadly, they include most salad foods, such as lettuce, onions, cucumber, radish, and mushrooms, and they also include colored vegetables, such as broccoli, green beans, bell peppers (sweet peppers), and Brussels sprouts. These are considered "Green-Green," "Green," and "Green-Amber." Under "Green-Green," we have separated out the vegetables that have the high concentrations of background micronutrients that our ancient ancestors delighted in. You can have unlimited consumption of these foods, and the ideal is up to two pounds (900 g) per day. ~Paleo in a Nutshell p.62
Not all underground vegetables are starchy. For example, turnip and radish, which both originated in Asia, are non-starchy, as are bulbs such as onion and garlic from Asia and the leek from the Middle East. Corms such as Chinese water chestnut are also non-starchy. Unlike the starchy roots, they mostly get their bulk from another com pound called "inulin." ~Deadly Harvest p.56