There's a growing consciousness of health, fitness, and nutrition, which is great. Everyone is coming around to the idea that food can be medicine, and that our bodies have the ability to heal themselves when given the right tools. People are interested in losing weight, long-term health, and eating in a way that is sustainable for their lifestyle and doesn't feel restrictive. Of course, in such a climate, different diets crop up all over the place, everyone's an expert, and a reductionist mentality abounds. One example is the "keto" diet, short for ketosis. Its popularity has grown, so it's important to analyze the promises it makes - can it really deliver what it says it does? Does it promote health and longevity? Is it restrictive? There's so much contradictory misinformation floating around that we tend to gravitate towards listening to others' experiences and eying their physical results when trying to make a decision about how to eat. But this is incredibly risky, because as we (should) know, external appearance doesn't translate to internal health. So let's talk about it...
What is the keto diet?
Keto is a low-carb, high-fat, moderate-protein diet. It severely restricts carbs in an effort to get the body to turn to fat instead of glucose as its source of fuel. It first emerged as a way to treat drug-resistant epilepsy in children, and its benefits for that specific purpose are well-documented.
Currently, it's also being touted as a way to lose weight primarily, as well as improve insulin sensitivity in diabetics and prevent/treat neurological diseases. But just because the keto diet (which I'll shorten to "keto" from now on for the sake of brevity) serves one purpose successfully, doesn't mean we should jump to hasty conclusions about its other potential benefits.
In the event that your body doesn’t have enough glucose to use, the precious amount available is shuttled off and used primarily by the brain. Fat gets broken down into ketone bodies by the liver as the only other source of energy that can be used systemically, as well as cross the blood-brain barrier for the brain’s usage when necessary. This is an incredible emergency back-up mechanism that kicks in when our bodies need it, and the human body’s resourcefulness leaves me in awe - its careful division of resources, its ability to protect our most important physiological systems in the event of a crisis, and its sheer resilience. That being said, this should raise eyebrows already. Mild ketosis occurs during fasting (like overnight), but a prolonged state is abnormal. Is inducing a state of emergency really a good idea? Our body will cut corners when it needs to - for example, the functioning of the reproductive system is the first to go when your body doesn’t have enough energy to sustain all its systems. I’m not at all suggesting this happens on keto, but just highlighting that physiological sacrifices get made when necessary to preserve the most important systems that sustain life (like the brain and cardiovascular systems).
side effects of keto
First, I want to make a bold claim. Ready? There shouldn’t be any side effects to a truly healthy lifestyle. The fact that keto’s side effects need to be pointed out/managed and dieters forewarned is a red flag; they include the following:
the “keto flu” (which proponents say only occurs in the early stages)
elevated heart rate
Furthermore, severe restriction of carbohydrates means that beans and most fruits are out of the question - even though legumes have been found to be “the most important dietary predictor of survival in older people,” and the Global Burden of Disease found that the number one dietary risk factor is not eating enough fruit. Digestive issues occur because of the diet’s low fiber content; high fiber diets (from unprocessed foods) are associated with lower risk of disease and death. Headaches and fatigue may be due to water and mineral excretion, and ketoacidosis is a dangerous metabolic state that occurs when there’s a build-up of ketone bodies in the blood, causing the blood to become acidic.
One supposed benefit that keto advocates point out is that health parameters like insulin resistance, high cholesterol, and high blood pressure improve when on the diet - but all of these markers are associated with carrying excess weight. It’s likely that the weight loss in itself, not the diet, produces these positive changes. Furthermore, a meta analysis of studies found that low carbohydrate diets are associated with “significantly higher risk of all-cause mortality” in the long term.
Keto and weight loss
Can you lose weight on keto? Definitely. But what’s the goal? Is it to lose weight at any cost? The dangerous undercurrent of this mentality is that we should sacrifice what we can on the altar of achieving the ideal body. I strongly reject this. First, losing weight isn’t the hardest part - it’s keeping it off and sustaining the lifestyle change that represents the real challenge, and keto isn’t sustainable long term, especially because of its elimination of food groups most closely associated with longevity. Second, and more importantly, I think willingly going on a diet (no matter how temporary you tell yourself it is) that has known side effects in order to achieve quick weight loss is destructive to your self-esteem and harmful to your physical health. It perpetuates the idea that our worth is directly tied to our appearance. Is that the culture we want to contribute to? But I get it. You’re tired of dieting, and it’s something to try. So let’s talk about why you shouldn’t go on the keto diet to lose weight.
First, ketogenic low-carb diets (defined as any diet that induces ketosis) have no advantage over nonketogenic low-carb diets. In this study, all food was provided to participants over a six week period. They both experienced the same amount of weight loss, but along with the keto diet came adverse side effects - the study’s authors concluded that “the use of ketogenic diets for weight loss is not warranted.”
Second, keto diets are subject to the same pitfalls of any other diet - namely, if you’re not in a caloric deficit, you won’t lose weight. The exact mechanism for weight loss on keto is unclear, but one theory is that the diet causes a decrease in appetite stimulating hormones, and the dieter eats less as a result. However, not everyone may experience this, leaving you susceptible to overeating, particularly if you’re consuming processed food. A much healthier approach would be to eat high-fiber foods that aren’t calorically dense, like fruits, vegetables, whole grains, and legumes. You wouldn’t need to do any counting or calculating, the fiber would keep you satiated and full, and you could rest assured knowing whole plant foods promote health and longevity.
Finally, the big “gotcha” is supposed to be that one loses weight more quickly on a low-carb diet than a low-fat diet. Personally, I don’t believe in reductionist approaches to nutrition, but I do want to point out a discrepancy here: diets classified as “low-fat” in research are diets that derive 30% of calories or less from fat, while “low-carb” diets derive 10% of calories or less from carbs. I would be interested to know how subjects fare on a truly low-fat diet of 10% of calories or less from fat. Even the existing comparison isn’t conclusive, however. POUNDS LOST (Preventing Overweight Using Novel Dietary Strategies) was a two-year study that found that healthy diets of a variety of macronutrient ratios worked equally well for weight loss in the long run. In addition, low-carb diets seem to only be beneficial for heart health if the fat and protein come from vegetable sources; low-carb diets high in animal fats and proteins don’t produce the same results.
Keto and diabetes
Does the keto diet cure/help manage diabetes? On the surface, that appears to be the case - but let’s take a deeper look at why a high-fat diet actually increases insulin resistance (a condition in which your body is resistant to the hormone insulin, causing elevated blood sugar), and does damage to diabetics in the long term.
We’ve known for close to a century that insulin resistance can be induced by high levels of fat in the blood which “[cause] insulin resistance by inhibition of glucose transport”. Practically, this means the more fat you’re consuming, the more insulin resistant you become. But this seems to contradict what those on the keto diet experience: their A1c levels drop and blood glucose flatlines. We need to treat these results with nuance to understand why they occur, and what they mean.
Blood glucose spiking in response to carbohydrate-rich foods is a symptom of insulin resistance, not the cause. If you’re consuming a low-carb diet, your blood glucose will stabilize because you’ve lowered your carbohydrate intake, and your A1c level will drop because there’s less glucose to bind to. However, these numbers don’t tell the whole story - to accurately determine insulin sensitivity, one must test their glucose tolerance by consuming carbohydrate rich food or drink. Diabetes has been cured when glucose uptake into cells is measured to be normal, in conjunction with healthy fasting blood glucose/A1c levels. The latter alone doesn’t tell the whole story.
For a detailed list of misconceptions about the keto diet and diabetes, check out this article by Dr. Cyrus Khambatta of Mastering Diabetes.
Keto and neurological diseases
The keto diet successfully treats drug-resistant epilepsy in children and has been shown to for decades. However, does that mean it can be used to treat other neurological diseases (such as Alzheimer’s and Parkinson’s)? The answer is, we’re not sure. It has been shown to have neuroprotective effects in animal studies, but there’s no guarantee the same efficacy translates to humans. Furthermore, if you’re healthy, you can implement other lifestyle changes (like exercise and consistent quality sleep) that have been shown to improve cognition and memory in humans. So if you’re looking to keto for protection from neurological disease, know that there are other effective tools at your disposal.
what about a whole-food plant-based keto diet?
Suppose you want to try keto, but decide to consume only whole, plant foods. Score, right? Not so much. You would still have to cut out whole grains, legumes, and fruit, which are incredibly health-promoting foods, as explained above. You would have to severely limit the variety of vegetables you eat, which could leave you susceptible to nutrient deficiencies. You would also have to consume high quantities of oil, which is nutrient-poor and impairs endothelial function.
A whole-food plant-based diet should be diverse, rich in micronutrients and phytochemicals, high-fiber, fun, satisfying, filling, energizing, and straight-forward. In someone with no disease, there should be no need to count calories, track macros, or be cautious of inducing dangerous metabolic states.
I envision a world where we can truly enjoy nourishing food, and the way our bodies look has slipped from the mantle in favor of good health. I realize this piece will probably be frustrating to some people. I’m not interested in kicking up controversy for controversy’s sake. I think it’s important to be honest with ourselves about what our motivations are and what pushes us to make lifestyle changes. The keto diet has come to the forefront because of what it promises about how it’ll make us look - period. And like I said above, I get it. I understand the temptation of that (I’ve been there myself, which I’ll talk about in a later piece). But that’s not the way forward. It doesn’t increase longevity. It has unpleasant and potentially dangerous side effects. It isn’t sustainable and it can’t promise long-term results. The path to health can be challenging because it involves a change of habits and an adjustment in behavior, but I don’t believe it should be painful, and it certainly shouldn’t be driven by low self-esteem or poor self-image. We have better reasons to get healthy! We have so much to offer the world, and we need to be our healthiest selves to do it! I encourage thoughtful debate; let me know what your thoughts are below.