The Optimal Eating Pattern for Long Covid?
Here's One Reasonable Hypothesis
Human nutrition is complicated stuff. Even after decades of research, there are still splits in the medical community, still lots of things we are not really sure about. And talking about nutrition can be like talking about politics or religion — people have rather strong opinions. But you gotta eat, so let’s consider a recent study that put forward a reasonable hypothesis: long haulers might want to start with a keto diet for a short period, then transition to a Mediterranean diet.
“From the Ketogenic Diet to the Mediterranean Diet: The Potential Dietary Therapy in Patients with Obesity after CoVID-19 Infection (Post CoVID Syndrome).” Current Obesity Reports, 6 May 2022, PMID 35524067.
Phase 1: A Ketogenic Diet
Ketogenic diets (also known as ‘low-carb’ diets) involve strictly limiting carbohydrates, getting adequate protein, and getting a majority of calories from fat. Ketogenic diets have been medically prescribed for certain types of childhood epilepsy that are resistant to other treatment, but most doctors are leery of this option for any other purpose.
Ketogenic diets (and low-carb diets in general) put the body into a state of ketosis - instead of relying on glucose as the primary energy source, the body is burning lots of ketones - which are modified forms of fat. When the body doesn’t get enough calories from an ordinary diet, it turns to the body’s own fat reserves. Stored fat is liberated, and it is converted to ketones to keep the metabolic processes running. In a ketogenic diet, food choices limit what fuels the body has available, and it changes the fats that are consumed throughout the day into ketone body compounds. These ketones compounds have a distinct aroma (similar to acetone in nail polish remover), and they come out on the breath when a person exhales.
» The Researcher’s Rational for Keto
The Italian paper proposed that long haulers start with a ketogenic for 8-12 weeks for several reasons:
Improve endothelial function damaged by acute covid infection,
Repair skeletal muscle damage from acute covid infection,
Induce certain anti-inflammatory mechanisms,
The paper proposes a high protein, low fat, low calorie keto phase (approximately 800 kcalories per day). They further divide that into 3 stages, starting with intake that involves more amino acids (pre-digested), and which moves towards high protein meats for lunch and dinner.
» Ketosis to Reset Insulin Resistance
Restricting carbohydrates (ie, “Going Low-Carb”) is an established way to reset insulin tolerance or resistance. 1 This is a state where insulin is still being produced, but the insulin loses effectiveness in signalling the cells to open and take in glucose. As a result, the body produces more and more insulin, which has less effect … and blood sugar and triglycerides rise. This mechanism is different from Type I Diabetes (where insulin levels are very low due to damage to the pancreas) but the bottom line is quite similar … cells don’t get the insulin stimulus the way they should, and problems arise.
» Limits of a Ketogenic or Low-Carb Diet
Twice I have gone on low-carb diets. The first time I did that, I saw a dramatic reduction of panic attacks that I had been having daily. I attribute this to the way that ketones work on the nerves - they not only can prevent epilepsy, are generally calming and sedating. And the cause of my panic attacks may have had their roots in blood sugar issues (I tended to get very shaky and jittery in a way consistent with low blood sugar, and eating helped, at least temporarily).
Both times I went on a low-carb diet, I developed psoriasis after 2 or 3 months. I had never had psoriasis in the 35 years prior to that, and the psoriasis went away and stayed away since. I speculate that switching to a low-fiber diet changed the bacteria in my gut, and that eating lots of meat revved up and glitched part of my immune system. Maybe that speculation is off base, but getting psoriasis twice after going low-carb is an unmistakable sign.
Many kidney specialists are worried that in the long run, low-carb diets will mean more kidney disease for millions of people. We need protein, but protein makes the kidneys work harder … more is not always better. This might not be a factor if the carbs are replaced with fat instead of protein in a ketogenic diet. But in the long term, high-fat might cause other problems.
Many have been conditioned to see their food choices through a simple equation: Fat = Bad. But nutrition always involves more than one variable, and it is more likely that large amounts of fat can be bad under certain conditions, but might actually be good under other conditions. The assumption that more fat will cause an increase in LDL cholesterol and raise risk for heart disease is not what we see in the research; low-carb and high-fat diets can improve the blood levels of these markers of risk. 2
But what are the long term consequences of eating a diet that is 60% or more fat? That is debatable. In the short run, a ketogenic diet may not create many problems. We don’t know as much about the consequences in the long term.
Another big factor that limits low-carb diets in the long run is the limited types of food they allow. Low carb diets get boring, and that makes it harder to stick with them.
» The Evolutionary Paradigm of Diet.
From an evolutionary perspective, humans are omnivores. We can (and probably should) eat a wide variety of foods. Some meat (but not too much). Some carbs (but more of the fiber-rich ones, and not so much the refined starches and simple sugars). Less fructose and sucrose than we currently consume, as that fattens up the liver and deranges insulin metabolism. A diet that is too restrictive in any one direction is probably bad in the long term.
There are a number of studies of cultures around the world where people eat a fairly high-carb diet and don’t experience the ills we see in western diets. Granted, these people are active instead of sedentary, they are probably getting lots of sunshine and vitamin D, they are probably doing other things that help make the high carb diet tolerable. But they don’t have insulin resistance. Carbs can be good food when insulin homeostasis is healthy, and carbs become terrible food when insulin homeostasis slips and cannot be maintained.
That’s why this study called for a short-term ketogenic diet, followed by a switch to the Mediterranean diet. In terms of our evolution, there is more evidence to eat like a Greek peasant than an eskimo - once the insulin is back under control.
Phase 2: A Mediterranean Diet
In the paper, the researchers proposed transitioning over to a Mediterranean diet that is characterized by lots of plant foods (vegetables, whole grains, fruits, legumes, nuts and seeds) along with moderate consumption of dairy (milk and yogurt), fish, eggs (4 or fewer per week), low intake of red meat and sweets, and moderate or low intake of alcohol (mostly red wine with meals). Olive oil serves as one of the major sources of fat.
Mediterranean-styled diets have a great deal of support from the medical community; many see them as ideal for longevity and health in the latter half of our lives. The Mediterranean diet is similar to the “Blue Zone” diet idea that arose from studying areas around the world associated with longevity.
Some researchers have focused on the olive oil component of a Med diet, and that may be a factor. The monounsaturated fats in olive oil may be very healthy themselves, while fresh virgin olive oil is rich in a peppery molecule called oleacanthal that has an anti-inflammatory effect like Ibuprofen, and other molecules like oleuropein and hydroxytyrosol that might stabilize many metabolic functions. 3 4
Other factors may play a role in the healthiness of a Med diet. This pattern of eating traditionally has included a lot of certain spices (from the familiar garlic and oregano to less well-known spices like sumac and large amounts of sesame seed). These herbs and spices are loaded with biologically active molecules which may contribute to the Mediterranean Diet’s good effects.
Mediterranean Diet or Mediterranean Lifestyle?
In Greece, where this way of eating has been widely studied, the people in the rural villages also tend to have strong social connections, they lead physically active lives, and many engage in periodic fasting according to the Orthodox Christian traditions. It isn’t clear how much of the longevity and low rates of heart disease are due specifically to the diet, and how much is a result of other lifestyle factors.
Safety
Most doctors consider a Mediterranean pattern of eating to be the ideal long term pattern. It is consistent with the common ideas of prudent eating.
A short-term ketogenic diet is an intervention or lifestyle change that is not generally high risk, although people with other medical conditions are advised to consult their medical professional to see if there are special concerns. Switching from one pattern of eating to another can often lead to a few days of disturbance as the body changes gears to be able to process a very different set of foods.
The idea that people should limit calories while convalescing from any disease is a bit controversial. Proposing a daily intake of only 800 calories might not be a good idea if someone has a low body weight or body mass index (BMI). Many of the benefits of ketogenic diets are seen even when calories are not limited.
Cost
The cost of eating by ketogenic ideas for a few weeks, and then switching to a Mediterranean diet are modest. Olive oil costs a bit more than corn or soy oil. Refined, processed foods like ramen noodles are cheap, while fresh fruits and veggies cost more. It is worth noting that almost every nutritional authority has long recommended eating fewer processed foods, and they all advise people to eat more fruits and veggies.
The biggest costs associated with the proposed diet are not financial - they involve time and effort.
Evidence
The proposal for these dietary changes for Long Covid have little direct evidence. At the time they published their paper, it relied on theory based on research using other populations (ie, the elderly with muscle wasting, people with metabolic syndrome or diabetes, etc). They did not present data on how people with Long Covid responded to the diet (presumably, that will come later).
The Bottom Line
This paper presents an interesting proposal; it is highly speculative, but it has a rationale that makes sense. We know that changes in diet can have effects on the body. People have to eat. It is impossible to say whether this approach will prove to be valuable for long haulers or not. It would be nice to see actual studies that compare what happens when one group of long haul patients make these changes while another group of long haulers does nothing and keeps eating however they like. That would be of value. I will be looking to see if any such research is published, and I will be writing about it here if it does come out.
“Efficacy and safety of low and very low carbohydrate diets for type 2 diabetes remission: systematic review and meta-analysis of published and unpublished randomized trial data.” BMJ Clinical Research, 13 Jan 2021, PMID 33441384.
“Effects of a low-carbohydrate diet on insulin-resistant dyslipoproteinemia-a randomized controlled feeding trial.” American Journal of Clinical Nutrition, 11 Jan 2022, PMID 34582545.
“An Olive Oil Compound That Makes Your Throat Itch May Prevent Alzheimer's.” Scientific American, 1 Jun 2013, www.scientificamerican.com/article/olive-oil-compound-makes-throat-itch-prevent-alzheimers/#
“Biological effects of olive oil phenolic compounds on mitochondria.” Molecular and Cellular Oncology, 20 Mar 2022, PMID 35340790.
