I’ve been reading some of the barrage of articles about fasting and Ketogenic diets. Some of what I’ve read is based in fact, sprinkled with fairly insignificant errors. But some of what’s out there is just not factual. Some of the arguments that use biased or incorrect information, or faulty research design are extremely frustrating for me as a public health dietitian/nutritionist.

One outcome of my reading is that I recognize that there is now a huge number of different spins on the keto diet and associated fasting; some without the fasting and some with fasting and all kinds of variations of what’s allowed and what’s not allowed. It really is a fact that eating refined carbohydrates (sugar, refined grains and all kinds of highly processed foods) is not going to deliver optimal health. But permanently cutting out all fruit, legumes, whole grains and starchy vegetables is likely not an optimal decision either.

I have encouraged people for years to embrace the type of diet that works for them; with the caveat to choose an eating-style that reduces simple sugars, refined grains, and highly processed foods. You can eat a high protein diet and still follow my recommendations. You don’t need to eat red meat at all if you don’t want to and can still embrace a high protein diet. Fish, chicken, eggs, vegetables or whole grains and legumes all can contribute to the high protein goal.

Since it is true that you can obtain high protein without red meats, and that there are good things in both the Keto/fasting and the plant-based Mediterranean-style eating, I rejected the approach of pitting one against the other in a clash of evidence. Instead, I’ll try a different approach. Have you ever heard a saying: “Judge them by their fruits”? (Matthew 7:16-20) It’s a saying in the New Testament that’s talking about false prophecies. The bearing of fruit is a metaphor that is used quite a bit in the Bible. But I’m not trying to teach a Sunday School Lesson today. I really like the metaphor, however in secular discussions like this one. And this is where my thoughts are taking me.

First, let me say that the plethora of writings about Keto/fasting is over-whelming for me. I can only imagine, that if you don’t have an education in nutrition, you may be over-whelmed too. And in addition, to being over-whelmed, you may not be able to spot the erroneous information. So back to my fruit metaphor, which lead me to think of the now-famous Blue Zones that I’ve written about a number of times in the past. If you’re not familiar with the Blue Zones and their outcome let me briefly tell you about them. They are four to five areas around the world that have high concentrations of individuals over 100 years old. The fruit their life styles has borne are long life, healthy bodies, and happiness with friends and family. In addition to pure longevity, there are also clusters of people who have grown old without health problems, including heart disease, obesity, cancer, or diabetes. Dan Buettner has written a book interestingly called The Blue Zone Solution.

Several of the factors of those who live in the Blue Zones are social, but one of the uniting factors of the Blue Zone peoples is that they all consume moderate calorie intake and semi-vegetarian, plant-based diets.

Aside from my bias of being a fruit-lover, I can’t imagine turning my back on an entire group of plant foods that are so rich in phytonutrients. Phytonutrients are a wonderful and ginormous group of nutrients that work to keep our cells healthy; and are also involved in healing when cells are injured. That’s all I’m going to say about the idea of “booting” fruit from your diet.

Here is a little common sense rule of thumb that fits this discussion: If an eating-style causes you to have one of more of these side-effects I have been reading about in the keto-fasting literature you should ask yourself some serious questions. The list includes headaches; dizziness; intense hunger; hypoglycemia (low blood sugar); electrolyte/mineral deficiencies; bad breath (keto breath); brain fog; fatigue; irritability, depression; flu-like symptoms (keto flu); sleep problems; heart palpitations; dark circles or bags under the eyes; bleeding gums; hair loss; muscle cramping or twitching; edema/swelling; numbness or tingling; clicking joints; canker sores; cracks in the corner of the mouth; painful tongue; loss of smell or taste; unusual nosebleeds; easy bruising; acne during menstruation; frequent urination; constipation; or diarrhea could it be that the eating-style is less than optimal? Could your body be trying to let you know something is wrong?

I noticed in several of the articles that I read that they cited a study to make their point. I do that from time to time; but it’s usually to add to a huge body of evidence that is already established. Don’t base your decision, a decision as important as how to eat – how to nourish your body upon a single study that says something contrary to a huge established body of multiply-validated research.

So let me just end this blog with this point; if you’re confused about what kind of food to eat, consider judging what kind of diet supports people living long healthy lives. In my professional opinion, the closer we are to eating a highly-plant based eating style, the more likely we are offering our bodies the healthy nutrients they need, at a lower calorie intake that will support a healthy body.