While keto (ketogenic diet) is a current fad, low-carb diets are nothing new. The low-carb concept has masqueraded under many different names, with the most popular version (apart from keto) being the Atkins diet.
By this point, we’ve all heard wild low-carb success stories. But are claims of fat loss, improved energy, and reduced bloating worth the risks an intense low-carb regimen brings?
What does it mean to “go keto”?
The name “keto” or “ketosis” diet comes from the idea that if you starve your body of carbohydrates, it will have to start burning fat for energy, causing it to enter “ketosis”. During ketosis, which is a normal metabolic process, acids (called ketones) build up in the body.
Being on the keto diet means getting most of your calories from fat, and cutting way down on carbs. The calories in this diet are approximately 60-80% fat, 15-35% protein, and 5% or less carbohydrates.
Keto diet approved foods include:
- Dairy: full-fat plain yogurt, cream, cheese (milk is often considered too high in natural sugars)
- Meat: bacon, red meats, fish and seafood, poultry, eggs
- Nuts: most nuts are allowed in relatively small amounts (they do contain carbs)
- Oils & Condiments: coconut oil, butter, olive oil
- Fruit & Vegetables: greens, peppers, eggplant, tomatoes, avocados, berries
- Sugar, pasta, bread, rice, beans, corn, non-berry fruits
How well does it work for fat loss, and what are the potential benefits?
In the short term, it can seem like it works better than a conventional diet. However, research shows that while initial weight loss may be faster than on a different diet with the same calorie count, the majority of this quick weight loss is due to decreased carb and water retention. As a result, 12 months into the diet, fat loss is on par with a different diet that does include carbohydrates (study here). While a summary of randomized controlled trials comparing low-carb and low-fat diets suggests that low-carb diets lead to more weight loss, many of these studies did not control for the quality of the foods involved. When research ensures both diets include equally “healthy” foods, weight loss is the same.
- Many individuals find they feel less hungry (due to fat’s satiety promoting effects), which can make it a more comfortable way to eat fewer calories
- Some people experience more consistent energy, likely as a result of eating fewer “simple” carbohydrates that can lead to blood sugar spikes and inconsistent energy
- Fat loss, as with any diet that involves eating fewer calories than your “maintenance”
- Fewer empty, carb-based calories in your diet like white bread, baked goods, cereals, desserts
- Increased intake of healthy fats and associated nutrients, like those that come from avocados and salmon
- Can be used to manage particular diseases and metabolic conditions
Keto can be a helpful short-term option, and it works for some people as a way to jump start their fat loss. However, it comes with risks, and definitely isn’t a safe option for everyone. The risks associated with an individual’s keto diet intensify as the low-carb component of the diet intensifies, and, of course vary person-to-person.
10 Potential Risks of the Keto Diet
1. Cardiovascular complications
Because many of the animal-based, saturated fats associated with the keto diet are associated with high cholesterol and heart disease, it can be dangerous to you cardiovascular health. Many fats, like those found in avocados, are beneficial. Others, however, are a bit more artery clogging. Some descriptions of the keto diet don’t specify the importance of limiting partially hydrogenated oils (trans fats), but given their dangers you should. Some research has shown that going on the keto diet increases cholesterol and triglycerides, while others have found it to decrease heart disease risk (review here). Getting as much of your fat as possible from unsaturated, plant-based sources will minimize your risk.
2. Lack of longevity
The longest-lived populations in the world (blue zones) get a large portion of their calories from carbohydrates. We don’t fully understand how a lifetime of eating low-carb can affect longevity. But if you look at cultures around the world, high meat/animal product consumption generally comes with shorter lifespans. On top of that, a recent, global study found that people who lived the longest tended to get about half of their calories from carbohydrates.
3. Kidney stones
When researchers placed 195 children with epilepsy on the keto diet (for epilepsy), 13 of them developed kidney stones. This likely because of an increased intake of processed meats. Research shows high animal protein consumption is associated with high uric acid in your urine, increasing your risk of kidney stones.
4. Mineral deficiency and dehydration
Sodium, potassium, magnesium, and calcium will all be shed at a higher rate if you’re on a keto diet, leading to dehydration. You are especially at risk for it if you exercise or sauna with any level of frequency, as you’ll also lose these electrolytes through your sweat. Make sure you are consuming enough of them as part of staying hydrated. Otherwise, your experience of the short-term “keto flu” will be worse. You’ll experience stronger symptoms of fatigue, constipation, nausea, headaches, etc.
5. Other deficiencies
A lack of consumption of whole grains also increases the risk of missing out on certain nutrients. Something as restrictive as keto should be as well-researched and well-rounded as possible. Adding seeds like chia and flax as well as adding more greens to your diet will help.
6. Digestive issues
Low fiber intake is associated with digestive problems, as insoluble and soluble fiber play key roles in nutrient absorption and microbiome maintenance. In contrast, high fiber intake is associated with many positive health affects, even beyond the bowel.
7. Hard to stick to
While you could say this of any restrictive diet, keto is a pretty extreme case of restriction. In fact, this meta-analysis found that of people who were actively trying to eat in line with the diet for medical reasons (epilepsy), over half didn’t.
8. Rapid weight gain
Since keto puts your body into starvation mode and you retain minimal water, as soon as you go back to carbs (and higher calories) you’ll probably gain weight very fast. Because it’s such a difficult diet to maintain, most people will end up transitioning out of it, and many will quickly gain back whatever they lost.
9. Insomnia, mood, and hormone changes
Interfering with carbohydrates means messing with the production of neurotransmitters and hormones like serotonin and melatonin. Your body relies on carbohydrates to build serotonin, a chemical associated with digestion and with mood. You use those same building blocks to build important things like melatonin, your body’s “sleep” signal that is produced when it is dark out. Many people who go keto experience insomnia or find themselves sleeping much less, likely a result of this interference. Shifts in hormones that affect menstrual cycles can also occur, leading to further complications (which can be positive if you have PCOS).
10. Sub-optimal athletic performance and muscle loss
You see vegan weightlifters at the Olympic level, but at this point you won’t find any professional athletes who are on a strict keto diet all year. Carbs help build and maintain muscle, and they’re generally a more efficient fuel for your body. If your exercise is just for fun and fitness, then you can probably maintain your lifestyle on a keto diet. Your body will adapt, and become better at using fat as fuel, which may be useful for endurance (review here).
Even with all the potential risks, going keto works really well for some people. If you’re on a keto diet and love it and what it’s doing for you, there’s probably no reason to stop.
However, being aware of the risks can help you know how to mitigate them. In keto’s case, this might mean favoring avocados over bacon, choosing not to restrict your fruit and vegetable consumption as strictly, or at least rotating your vegetables to get a larger variety of nutrients.
Just because an intense keto diet may not be the best long-term solution for optimal health doesn’t mean there’s nothing to learn from it. A more well-rounded approach to dietary change should still include plenty of healthy fats, for example. Cutting out refined, “empty” carbs is also an excellent step. Perhaps try combining the low-carb idea with other eating styles you prefer, like low-carb paleo or low-carb Mediterranean.
The best “diet” is the one you can comfortably, happily, healthfully maintain.