When it comes to nutrition, it is wise to be cautious of advice that seems too good to be true. An example of this is the hype surrounding the use of very low carbohydrate diets, like the ketogenic diet.
Historically used to treat severe epilepsy, the ketogenic diet is promoted as a way to lose weight; improve brain function; control blood sugar, cholesterol, triglycerides, and blood pressure; reduce inflammation; and the list goes on.
However, research on the impact of these diets is limited and based on very short term studies (weeks, months, or at best, a couple of years). And while some may seem promising, if you hope to follow a healthy living pattern for another three, four or five decades, it’s good to get the full picture on what the evidence is (or, in this case, isn’t) before making any huge dietary changes.
What is a ketogenic diet?
Carbohydrates are your body’s preferred energy source, and they will be used first. If you are mainly eating fat, your body will burn (metabolize) it, pushing you into a state of ketosis. A ketogenic diet restricts carbohydrates to the point that your body goes into this state.
Are there side effects to burning fat for energy (ketosis)?
It appears that most people on the ketogenic diet lose weight at the outset, mainly due to its rigid restrictions. And at least in the short-term, this has been shown to lead to positive outcomes such as improved blood cholesterol and blood sugar. But there are negative side effects too. Even in healthy people, constipation, nausea, fatigue, and headaches are common. The bigger problem is that research is lacking on what the long-term effects are on the body. Not only do we not know what the cardiovascular risks are, people following a ketogenic diet may be at increased risk of the following:
- elevated uric acid (which may worsen kidney disease and cause inflammation in joints)
- vitamin and mineral deficiencies
- bone mineral loss
- kidney stones
And there may be other effects we aren’t even aware of yet.
How low is “low carb” when following a ketogenic diet?
Health Canada currently recommends that 45-65 per cent of calories come from carbohydrates. For a person eating 2000 calories per day, this is 225 to 325 grams of carbohydrate per day. To develop ketosis, most people need to restrict carbohydrate intake to about 50 grams per day. To put this amount into perspective, there are 40 to 50 grams of carbohydrate in the following foods:
- 1 cup of cooked spaghetti or quinoa
- 3 cups of cooked carrots
- 1 ½ large apples
- 4 cups of milk
- 1 can of pop
Now, before you get excited and think that doesn’t sound too bad, you can pick only one of those items, not all of them when following a ketogenic diet. And this doesn’t factor in all the other sources of carbohydrate in your diet, like cucumber. Yes, cucumber has almost 5 grams of carbohydrate per cup.
If people aren’t eating foods with carbohydrates, what’s left? People on a ketogenic diet focus on low-carbohydrate vegetables, high-fat milk products, meat, fish, poultry, eggs, and nuts and nut butters. Additionally, it may be recommended to eat something called “fat bombs.” (I’ll leave you to look that up.) While it’s commonly thought that these popular ketogenic diets are high in protein, they are not. About 20% of calories come from protein, which is similar to a typical diet.
Following a ketogenic diet is likely not a nutritionally balanced pattern of eating. It requires planning, some solid math skills, and being okay with how this diet may impact the social aspects of eating with your friends and family.
The bottom line: Restrictive diets don’t work over the long haul, and a single nutrient, like carbohydrate, is not our enemy any more than fat was the enemy in the 1980s. Instead, think about choosing moderate amounts of carbohydrate-containing foods as part of a healthy pattern of eating. And if you are thinking of trying a ketogenic diet, make sure you get the support you need. Your doctor can monitor your blood work. A pharmacist can manage any needed changes to your medications. And a dietitian can help you assess your nutrition goals and determine an individualized plan to minimize any potential risks to you and your health. To speak with a registered dietitian for free, call HealthLink BC at 8-1-1 (or email).