There was once a time when low-fat cookies, chips and peanut butter were considered “healthy choices.” Oh, how times have changed!
Ever since studies began surfacing showing that low-carb, high-fat diets can be more effective for weight loss than low-fat plans, more and more health-conscious folks have fully embraced fat. Sales of whole-fat milk and yogurt have soared in recent years, and most nutritionists now tell their clients to incorporate fatty foods like fish, avocado and olive oil into their diets. The reemergence of all this creamy goodness has led to a century-old diet making a major comeback: the ketogenic diet. Celebrities including Gwyneth Paltrow and Mick Jagger are both rumored to have taken the plan for a test drive.
Those following the keto diet plan eat a lot of fat and just a few carbohydrates. More specifically, 80% of the diet is comprised of fat, 15% is protein, and a mere 5% of kilojoules come from carbohydrates. For someone on a 6200 kJ diet, that translates to 19 grams of carbohydrates per day, which is less than what you find in a cup of green peas. (For some context, most people’s diets contain 55% carbohydrates, 30% fat and 15% protein.) The idea is that if you deplete yourself of carbohydrates, the brain’s preferred fuel source, your body will start breaking down fat for energy. When this occurs, the body goes into a state of ketosis.
But does this really fuel weight loss or make us healthier? According to one Spanish study of 20 obese adults, the answer is yes. For the study, participants were put on a low-calorie keto diet and lost an average of 40 pounds over four months. Another small experiment had a similar outcome. In a six-month Experimental & Clinical Cardiology study of 83 obese adults, those on the keto diet lost an average of 14kgs, while lowering their bad (LDL) cholesterol levels and increasing their good (HDL) cholesterol.
But not all studies on the keto diet are as promising. One study of 20 participants found that those on the diet didn’t lose more weight than those on a non-keto diet. But they did have fouler moods and higher levels of inflammation, which has been linked to a variety of conditions, including heart disease and cancer.
Since research on the keto diet is fairly limited and inconclusive, it’s important to educate yourself about the potential risks before trying it. Here, five things you should know before going keto:
It’s extremely restrictive.
Due to the strict limitations on carbohydrates, keto dieters eat mostly meat, full-fat dairy, and non-starchy vegetables like leafy greens. Since they’re higher in carbs, cruciferous and root vegetables like cabbage, cauliflower and potatoes are typically avoided. All grains and many fruits are also skipped—just one apple has more than the average daily allowance of carbohydrates on the keto diet. Keto dieters also tend to stay away from less obvious sources of carbs like store-bought shredded cheese, which is coated in potato starch.
But despite how limiting the diet is, diet experts say that with careful planning, you can still fit in all of your vital vitamins and minerals. However, to play it safe, you should work with a nutritionist to come up with a well-rounded keto meal plan.
The benefits and long-term effects are unclear.
Most trendy diets are either supported or looked down upon by nutritionists. However, the keto diet remains controversial.
On the one hand, dietitian Lori Chang, and a supervisor at the Center for Healthy Living at Kaiser Permanente West Los Angeles, says using a “cleaner” source of energy—ketones rather than quick-burning carbohydrates—can improve mood and energy levels. When you eat refined carbohydrates or just too many carbs in general, the blood is flooded with excess insulin, Chang says. "This can lead to a blood sugar rollercoaster that stresses the body and negatively impacts energy levels and mood. When you’re in a state of ketosis, however, ketone bodies don’t require insulin to cross the blood-brain barrier, which wards off unfavorable blood sugar levels."
Other experts say the long-term accumulation of ketones could be harmful. “Those ketones are emergency fuel sources, and we’re not meant to run on them long-term,” says dietitian Kristen Kizer. “Ketones are negatively-charged molecules, which means they’re acidic. When you build up ketone bodies in your system, you’re building up acid. One of the ways your body buffers acid is by pulling calcium from your bones.” Kizer also notes that the diet isn't very balanced and involves a very high intake of animal products, which generally do not protect against cancer, diabetes or other diseases.
If you do try the diet outside of medical supervision, Kizer says it’s important to test your urine with urinalysis ketone test strips to ensure your ketone levels don’t become dangerously high. Ketone urine test strips are also used by people with diabetes to determine if they’re at risk for ketoacidosis (DKA), a life-threatening complication that occurs when an individual doesn’t have enough insulin in their body. (Healthy ketosis is considered 0.5 to 3.0 mM blood ketones.)
It can cause dehydration, constipation and kidney stones.
Carbs hold fluids in your body (think of how bread soaks up water compared to a chicken breast), so when you cut back on the nutrient, extra water is excreted in your urine. This makes it vital for those on the keto diet to stay hydrated. Not only will drinking extra water ward off constipation, but it can also lower the odds you'll get the “keto flu,” a period of fatigue, headaches, and pain, often caused by dehydration and loss of electrolytes.
Stay hydrated with this sassy water recipe:
Other side effects of the diet may include an increased risk of kidney stones (due to dehydration and acidic urine that’s high in calcium), bad breath, muscle cramps, and dizziness. Further, depending on how you choose your fats, the keto diet can also contain an abundance of saturated fat, which raises levels of dangerous LDL cholesterol and causes atherosclerosis, the buildup of fats and cholesterol in the arteries. If you decide to go keto, have a doctor monitor your cholesterol levels monthly to ensure you remain within a healthy range.
It’s not a foolproof weight loss plan.
Not only are study results split, but real folks following the diet outside of a lab also report varying results.
Heather Wharton, a 35-year-old business relationship manager, lost 63kgs since starting the keto diet in January 2016: “I plan on being on the keto diet for the rest of my life,” says Wharton. “My husband and I consider ourselves to be food addicts, and the keto diet is what we use as a form of abstinence from trigger foods that have sugar and other carbohydrates." A typical day of eating for Wharton includes coffee with a protein supplement, a cup of unsweetened cashew milk, cauliflower rice with ground turkey and liquid aminos (a carb-free substitute for soy sauce), spinach, six slices of turkey bacon, six eggs and a little salsa.
Others consider the keto diet a short-term solution for weight loss. Tyler Drew, a 34-year-old real estate broker, first read about the diet on Reddit and used it to lose 20kgs in six months before returning to a traditional diet. While on the keto diet, Drew’s cholesterol levels improved, even though a typical day of eating involved bacon at both breakfast and dinner.
For others, however, ketosis can cause more negative than positive side effects. Dorena Rode, a 52-year-old author and speaker, tried the diet for a month and experienced heart palpitations and dizziness. Unlike Drew, Rode says her cholesterol increased from 192 to 250 mg/dL after she introduced more fat into her diet. (Less than 200 mg/dL is considered desirable, while anything over 240 mg/dL is considered high.)
Talk to a doctor before trying it—really, though!
You’ve heard this line before, but really: Check with a doctor before trying this diet. The keto diet is an extreme eating regimen that could be harmful to certain people. It may not be right for those with heart disease, type 1 diabetes, or type 2 diabetes not controlled by insulin.
Although experts like Kizer have concerns about the keto diet, if you’re set on trying it, a doctor can help you determine if it is right for you and provide you with tools and information for accurately tracking your ketosis status.
If ultimately you decide that the keto diet isn’t for you, including a blend of healthy fats in your diet can still protect your brain, raise good (LDL) cholesterol, lower risk of heart disease, and help you stay satiated throughout the day.
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