Avocado, coconut, olives, cacao, coffee, lemons, and limes are plenty suitable for keto. Just remember that fruits are carbohydrates, first and foremost, (except for, arguably, the coconut), so don't go overboard. Granted, lemons and limes are virtually sugar and calorie free, so those can be considered "freebies," so-to-speak.
Not what you had in mind?
In the three years that I've been ketotic, I've probably fielded this question at least a hundred times. Family, friends, coworkers, roommates, and classmates of mine all seem to get either a) concerned, or b) shocked in disbelief, when I tell them, or remind them, that "yup, I still don't eat fruit," (at least not the kinds of fruit that they are most likely thinking of). In these scenarios, I don't bother to get specific because the word "fruit" is synonymous with "sweet," at least in the context of a juxtaposition with vegetables; so even though most people know that avocados and tomatoes are fruits, those types simply aren't the types that they're referring to when they inquire as to the frequency, (or lack thereof), of my fructose-containing-flesh consumption. Sometimes, I will say that I eat coconut, but that's about as far as I'll expound on the subject, unless someone is genuinely interested in keto, or is overtly trying to glean nutrition advice.
So, back to the fruit question.
If you're reading this blog, then you likely aren't new to keto, so I won't bother explaining what countless others have already explained much better than I could: why we don't eat high sugar, low fiber fruits, such as apples, bananas, and oranges. But berries - those are fine, right? Au contraire, my keto friends - not all berries are made equally, and therefore, not all berries are keto-friendly. For example, quite often, I see people say that blueberries are fine to consume on a ketogenic diet. I, personally, respond to this with caution.
Below is a chart comparing the nutrition of common berries: raspberry, blackberry, cranberry, strawberry, elderberry, blueberry, goji, and acai, all of which are sandwiched between two reference fruits: the coconut on the "GO!" side, (i.e., green), and the banana on the "STOP!" side, (i.e., red). The nutrition information given is per 100 gram serving, and is the most up-to-date, USDA certified info.
Berry Nutrition Comparison Chart
So just raspberries, then?
As you can plainly tell, the raspberry, with its 4 grams of sugar, 6 grams of fiber, 6 net carbs, and 1 gram of fat, is on the far left side. I gave it the #1 best berry for Keto rating, (despite that it has 1 net carb more than the blackberry), because it has 1 gram of fat more than the blackberry, and 1 gram of sugar, less. This could lead me into a discussion on why net carbs are not the whole picture, but aiming to keep these blogs short, I will save that for a future one. Just keep this is mind, and know the shorthand, which is that fiber and fat content help to blunt the glycemic response, and that glycemic response is best kept as low as possible when attempting to be in a ketotic state.
I chose to use raspberry as the flavor of "jelly" in our Peanut Butter & Jelly Thumbprint Gra-POW! Cookie Granola for this reason. But admittedly, not just for this reason - it also happens to be my favorite of the berries, flavor-wise. The third and final reason is that it's just plain traditional.
The traditional jam, or jelly, to use in this glorious cookie is raspberry.
Now, that said, I decided that adding a carton of raspberries to the mix would be just a bit too carb-y to offer as a ketogenic food. It didn't sit right in my heart, in other words. Instead, I experimented with raspberry powder and raspberry oil/extract in order to bring the same flavor to the table, while skimping on the sugar content. Ultimately, my goal is use similar methods to bring other fruity flavors into our future products, so if you miss fruit on your ketogenic diet, please stay tuned!