Low-carb diets have been cited as effective weight loss strategies for years. With the rise in popularity in keto meal plans—and the Atkins diet before it—more people than ever are considering cutting back on simple carbohydrates and sugar to improve their wellbeing. However, with any health matter, it's important to realize there are pros and cons to every radical change to your diet. And, it's important to note that consulting a doctor or licensed nutritionist is key to changing your food intake safely.
Several studies demonstrate that low-carb outperform low-fat diets in terms of weight loss, but that's not the only consideration when it comes to health and nutrition. Anecdotally, many people who try cutting carbs find that this approach might be too restrictive for long-term effectiveness. In short, there is a lot of conflicting messaging around consuming carbs, so we researched what actually happens to your body when you stop eating them.
We asked the experts about what actually happens to your body when you cut carbs. Here's what to know from nutritionists, dieticians, and doctors.
Meet the Expert
What Happens to Your Body After Cutting Carbs
As with any drastic change, there are a few things to consider. According to Kimberly Gomer, MS, RD, LDN, "every single time people cut carbs, they crave them." So, it's no surprise eating fewer carbs affects your body's functioning. Ahead, we break down what you may experience when switching to a low-carb meal plan.
You May Experience the "Low-Carb" Flu
Juliana Shalek, MS, RD, CDN, and founder of The Nutrition Suite claims that following a low-carb diet tends to promote weight loss at a relatively fast rate because cutting carbohydrates reduces blood glucose and insulin levels, which in turn minimizes fat storage in the body. However, Kristin Kirkpatrick, a dietitian at Cleveland Clinic, asserts that cutting carbs out altogether may result in fatigue, weakness, dizziness, headaches, irritability, and nausea that can last a few days or even weeks, also known as the "low-carb flu."
Gomer describes this phenomenon as well, saying you may have "brain fog and low energy." Glucose and carbohydrates are the preferred energy source for our brains, so adjusting to that intake inevitably has its effects. "If we have a high-end sports car, we put premium gasoline in it—so why give our brain sub-par fuel?" says Gomer.
Your Body Will Eventually Go Into Ketosis
If you cut out carbs completely, your body will eventually go into a state of ketosis where "small fragments of carbon called ketones are released into the blood because the body is burning fat instead of carbohydrates." Keto diets might sound appealing at first, but fat is a slower source of fuel than glucose, which means it takes longer for your body to access it, so it will be harder to get going during exercise and other activities.
Gomer agrees, adding that "we need carbs to exercise," so your activity level should be a consideration when trying out this approach.
Low-fiber diets can have a negative impact on both gastrointestinal and cardiovascular health.
You'll Lose Water Weight First
During a keto diet, you'll lose water weight first, which can be misleading, and then the non-water weight will follow. A 2013 meta-analysis published in the British Journal of Nutrition that compared low-carb ketogenic diets with traditional low-fat diets found that low-carb diets could be effective in reducing obesity rates. But when you consider the long-term health concerns mentioned earlier, cutting them out altogether doesn't seem like a healthy long-term option.
What About Going Low-Carb?
Celebrity nutritionist Kelly LeVeque told Chalkboard that we should also be looking at our food's "carbohydrate density" rather than cutting them out altogether. Put simply; carb density means the percent of the food mass that is carbohydrate minus the fiber component. As LeVeque explains, most high-net-carb foods will end up as sugar in your body. Whole foods in nature don't have a carb density over 30%; even carb-heavy vegetables will have a density well below that. It's processed foods that go well above that and, as we all know, should be avoided.
According to Gomer, an individual approach is key. "Most people are sensitive to processed carbs. There are people such as Type 2 Diabetics and highly insulin-resistant folks who do better eating fewer carbs," she adds. However, considering the potential negative effects of restricting your intake, it's important to consult a professional to find out what's best for you.
Why You Should Look For High-Fiber Foods Instead
The good news is, there are plenty of delicious, high-fiber, low-carb foods you can eat that will keep you feeling good. Since fiber is neither digested nor absorbed, it actually takes up space in your intestine, giving you a feeling of fullness (and making it easier to minimize snacking and overeating).
"High Fiber is gold," says Kimberly Gomer, Director of Nutrition at Pritikin Longevity Center. What's more, "eating lots of vegetables—the best carbs out there—is key for health," adding that along with making you feel satiated, veggies "will provide you with the nutrition that provides anti-cancer, strong immune health, and cardiovascular support."
Registered dietician nutritionist Maya Feller, MS, RD, CDN, of Maya Feller Nutrition, says that the daily fiber recommendation for women is 25 grams (although women over 50 should aim for 21 grams instead). "Most Americans are not meeting their daily fiber needs," the expert told us. "Low-fiber diets can have a negative impact on both gastrointestinal and cardiovascular health."
The Final Takeaway
So, in conclusion, do your research and prioritize eating healthy carbs that haven't been put through a refining process. Defined as whole grains, fruits, vegetables, proteins, and fats, nutritious fiber-rich foods will make you feel full and provide a host of health benefits. And remember, it's a personal process. Kimberly Gomer urges everyone who is considering changing their food intake to "work with a dietitian to develop the eating plan with the most appropriate carbs (how much and what kind) for the best health and energy outcomes."
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