Disadvantages of a Low-Carbohydrate Diet

For all the potential weight-loss benefits you stand to gain from a low-carb diet, there are some pitfalls to know about before you begin. Like any type of diet that restricts calories and foods, low-carb diets must be well-planned to avoid nutrient shortages. You should also be prepared for temporary issues like fatigue as your body adjusts. One worrisome issue isn’t related to cutting carbs, but comes from existing health problems that rule out a low-carb diet. If you have concerns, consult a registered dietitian or your doctor before changing your diet.

Nutrient Imbalance

A lot of diverse foods are allowed on a low-carb diet, including meat, poultry, fish, eggs, milk, cheese, fats and vegetables. If your diet contains a balanced mix of these foods, you shouldn’t need to worry about getting sufficient nutrients. But skimp on vegetables and you might end up short on fiber, vitamin C and vitamin K. Choose meats high in cholesterol-boosting saturated fat and your heart won’t be happy. Vitamin D is another nutrient to watch if you don’t get enriched dairy products.

Your daily carb quota also figures into the nutrition equation. Moderate carb intake of 80 to 130 grams daily makes it easy to get all your nutrients. A very-low-carb diet makes getting fiber more challenging, but here’s a tip: eat cooked vegetables rather than raw. For example, a half-cup of cooked broccoli has more than double the fiber of a half-cup raw. Plan your diet to include your recommended fiber intake -- 25 grams of fiber daily for women and 38 grams for men.

Temporary Side Effects

Carb Cycling Meal Plans

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Your body prefers to use carbs for energy because they’re easily digested into glucose. The sudden loss of glucose after cutting back on carbs may cause fatigue or brain fog, but not necessarily. One study published in the Journal of the American Dietetic Association in 2007 found that a very-low-carb diet caused energy to take a dive. In the same year, however, Obesity reported on a study in which participants noticed a decrease in fatigue when they started a very-low-carb diet.

Changes in your energy level should be temporary. If you go low carb and experience ongoing fatigue, be sure to check with your health care provider. Otherwise, you can prevent the problem by cutting back on carbs gradually. Begin by eliminating sweets and sugary beverages. Replace sugary beverages with water, tea, coffee, soy or almond milk and calorie-free flavored water or diet soda. Then, start reducing processed carbs, dropping about 5 net grams of carbs every three to seven days until you reach your carb goal.

Difficulty With Sustaining

The best diet is the one you can follow, advises the Harvard School of Public Health. Of course, the quality of the diet counts, but in the end, you have to stick with the plan to keep the pounds off. If you have a hard time eliminating carbs, or if you give it a try and keep falling off the diet, you may need to aim for 80 to 130 grams daily rather than 20 grams. The four phases of the Atkins diet demonstrate another option -- gradually increasing carbs. Phase One starts at 20 to 25 grams of net carbs daily. In Phase Two, dieters increase to 25 to 50 net grams of carbs. By Phase Four, the plan allows 80 to 100 grams of net carbs. The goal is to expand food choices and allow more carbs while supporting weight loss.

One good tip for staying on a low-carb diet is to think of it as a lifestyle change rather than a short-term weight-loss plan. Be sure to eat regular meals. Whether you prefer three meals and two snacks or six smaller meals, stay on a regular schedule. That way you’ll avoid getting so hungry you grab any snack -- low-carb or not. Finally, consider keeping a journal to track your progress. Taking notes on your diet, weight and activities keeps you accountable. It’s also motivating to see a record of pounds lost.

Health Considerations

Three Components of a Weight Loss Program

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A low-carb diet isn’t suitable for people with kidney disease, as high protein puts too much stress on the kidneys. But, a study in the November 2015 issue of Medicine offers reassurance for those worried about diabetes. A group of overweight people with type 2 diabetes followed a very-low-carb, high-protein, low-saturated-fat diet for 12 months without any change in kidney health.

High protein intake sometimes causes extra calcium to be eliminated from the body. As a result, low-carb diets have been associated with potential bone problems. The latest research suggests you don’t need to worry. A group of overweight adults who followed a very-low-carb diet for 12 months did not experience any change in bone strength, according to a study published in Nutrition in March 2016.

When carb consumption drops to about 20 to 30 grams daily, the body relies on fat for energy. As fat breaks down, ketone bodies are produced. That’s a good thing, because they provide energy. Ketone bodies are normally found in the bloodstream, but if their levels get too high, ketoacidosis develops. Ketoacidosis is primarily a concern -- and can be a medical emergency -- for people with diabetes and for anyone in long-term starvation mode.