Low carbohydrate diets have had dedicated adherents since even before the late Dr. Robert Atkins—a cardiologist—announced in 1972 that it was okay to eat red meat and cheese, and famously claimed that fat-rich macadamia nuts were a dieter’s best friend. And in the decades that have passed since the original low-carb revolution, a staggering amount of research has been done which indicates that reducing carbohydrates may be helpful for improving both type 1 and type 2 diabetes, atherogenic dyslipidemia, metabolic syndrome, PCOS, obesity, and neurological andneurodegenerative disorders. (Notably, some of these beneficial changes happen independently of weight loss!)
As low carb and Paleo diets have become popular among the general public, it’s not rare to see restaurants offering burgers wrapped in lettuce, non-starchy vegetables as sides instead of pasta or potatoes, and kitchen gadgets that turn zucchini and other vegetables into spiralized noodles can now be found in every home goods store. The variety of meats, vegetables, nuts, dairy products, and low-sugar fruits low carb diets allow make them a healthy strategy that’s not only delicious but also sustainable over the long term.
However, along with the benefits of eating this way come many potential pitfalls that can be the undoing of a patient’s best intentions. Here’s a quick look at some of the things that can derail a low carb diet—but it’s by no means an exhaustive list.
Low carb junk food and processed foods: Owing to the popularity of low carb diets, there’s no shortage of processed foods claiming to be “low carb.” While the total carbohydrate content of these products might be low, that doesn’t automatically make them health foods. Supermarket shelves are full of cookies, crackers, jams & jellies, yogurts, and other foods that contain artificial sweeteners and fillers, many of which may cause intestinal distress and discomfort. Moreover, one of the goals of low carb diets is to help people break their addiction to sweets and refined grains, and substituting low carb versions of these things only perpetuates the cycle. Sugar-free junk is still junk.
Poor quality fats: Here’s a place where low carbers can take a page out of the Paleo and Primal playbooks: while eating a large percentage of calories from fat is not a problem in the context of a low carb diet, those fats are better coming from pastured/grass-fed animals and cold-pressed, organic olive or avocado oils, rather than from omega-6 heavy soybean, corn, cottonseed, and safflower oils.
Overdoing it on fat: Many people discover the efficacy of low carb diets after years—decades, sometimes—of struggling to lose weight and boost energy on low-fat, low-calorie diets. So it’s easy to understand why these folks might go overboard on fatty foods, now that they’re “allowed” to have bacon, sausages, coconut oil and heavy cream. Keep in mind that it is possible to gain body fat on a low carb diet if someone is consuming far too many calories for their individual constitution and activity level. Patients who struggle to lose weight even on a low carb diet should be mindful of their total fat intake. They may eat fat as it occurs naturally in food—such as not cutting the fat off a steak or pork chop, and not draining ground beef after browning it in a skillet—but they don’t have to go out of their way to add a lot of extra fat to things, like a couple tablespoons of butter and coconut oil in their coffee. (The fatty coffee trend is catchy, but it may not be conducive to people reaching their fat loss goals.)
Lack of vegetable variety: In the quest to consume fewer carbohydrates, some people become overly worried about carbohydrates from vegetables and force themselves to stick to only leafy greens, broccoli, and asparagus, as if anything with a hint of color might be too sweet. This is unfortunate, because the produce section is loaded with a rainbow of vegetables and fruits that are perfectly suitable for low carbing, including eggplant, raspberries, tomatoes, bell peppers, and more.
Electrolyte imbalances: Due to the way insulin affects renal sodium retention, low carb diets (which typically reduce insulin levels) are naturally diuretic. Coupled with recommendations for adequate water intake that usually accompany all weight loss diets, some individuals may lose excessive sodium, potassium, magnesium, and other minerals. This is exacerbated by the fact that, provided the majority of the diet comes from whole, unprocessed foods, total sodium intake may be insufficient. (Most of the salt people eat comes not from fresh foods prepared at home, but from packaged, processed foods and fast foods.) While too much sodium may present a problem for some people, too little is no less harmful. (In fact, evidence suggests it’s not salt, but sugar, that is a primary driver of high blood pressure.) Individuals on low carb diets may wish to add a pinch of salt to foods they cook at home, particularly if they’re athletes and/or exercise regularly and sweat a lot. Prominent low carb researchers suggest drinking broth made with bouillon cubes during the transition to a low carb diet to ensure adequate sodium intake. Some people may benefit from potassium supplementation or consuming high-potassium foods that are low carb, such as avocados.
Falling off the wagon, face-first: While some people can quit starches and sugars cold-turkey, others need a more gradual transition. And some may find they’re able to stick to their plan most of the time, but once in a while, stress or cravings get the best of them and they dive into a pint of ice cream or polish off an entire sleeve of cookies in one sitting. Not the greatest thing to have happen, but not the end of the world, either. Individuals who have a “cheat” now and then but don’t understand about glycogen storage and water retention might be alarmed to see the scale go up anywhere from 2-5 pounds the next day. These people will feel completely dejected because they think one day—or even just one meal—of slipping has undone all the hard work they’ve done and all the progress they’ve made up until then. Of course, this is just water weight! When people first adopt a low carb diet, they typically lose a lot of water weight. The water they retain after a high carb excursion is simply the diuretic process in reverse. The increase in scale weight is It’s not body fat and it’ll be gone after a few days of returning to their usual low carb way of eating. It’s important for patients to understand this, because if they don’t, they may let their frustration get the best of them and turn one meal or one day into weeks or months of poor choices, and in that case, they can end up undoing all their progress.
Low carb diets can be extremely therapeutic for a wide range of health conditions. These pitfalls pale in comparison to the potential benefits, but it’s good for patients to be informed about things they should look out for as they transition to or troubleshoot their low carb life.
- RD Feinman, WK Pogozelski, A Astrup, et al (2015). Dietary carbohydrate restriction as the first approach in diabetes management: critical review and evidence base. Nutrition, Jan 31(1):1-13. doi: 10.1016/j.nut.2014.06.011. Epub 2014 Jul 16.
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- JS Volek, SD Phinney, CE Forsythe, et al (2009). Carbohydrate restriction has a more favorable impact on the metabolic syndrome than a low fat diet. Lipids, Apr;44(4):297-309.
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- Richard D Feinman and Jeff S Volek (2006). Low carbohydrate diets improve atherogenic dyslipidemia even in the absence of weight loss. Nutr Metab (Lond), 2006; 3: 24.