What’s the Keto Diet and Should You Be Following It?
Whether it’s for weight loss or digestive health, or for reducing the risk of chronic disease, everyone seems to be trying the keto diet lately. As a registered dietitian and personal trainer, I often get asked about the keto diet. I always like to present the pros and cons to every eating style and what the evidence says. So, does the research support its use? Read more to find out!
What Is the Keto Diet Anyway?
The ketogenic (keto) diet is a high-fat (75–80%), extremely low–carb (5%), moderate-protein (15–20%) approach to eating. This approach to eating puts your body in a metabolic state known as ketosis, where your body is using fat as its primary source of energy instead of glucose. Our bodies normally use glucose from carbohydrates as our main source of energy, and in states of starvation or altered metabolism, we turn to fat.
Ketones are a natural source of energy made from fat that is used by the cells of both body and brain. Ketones are produced in the liver when fat is broken down and used as energy. So yes, our brains can function without carbs, but they prefer not to!
The keto diet has been used medically in the treatment of epilepsy for a long time. Due to its effectiveness, it has been tested in the treatment of other medical conditions such as Alzheimer’s, multiple sclerosis, cancer, diabetes, and even heart health.
How Does the Keto Diet Impact Heart Health?
When it comes to heart health, we have typically thought of a diet rich in fats (especially saturated fats) as being detrimental to health. Some research is now suggesting that following a keto pattern of eating can improve HDL, LDL, and triglyceride markers. In addition, some studies have found improvements in hemoglobin A1c (blood sugars) and triglyceride markers when following a low-carb keto approach to eating.
However, the research is mixed. In fact, some research suggests it can increase the risk of hypercholesterolemia over time.
Bottom line: The diet can help improve blood-sugar markers and cholesterol levels; however, much more research is needed. Many other patterns of eating have also been proven to improve the same markers and reduce overall risk of heart disease, including a Mediterranean or vegetarian diet.
What About Weight Loss?
Many individuals following a keto diet tend to lose weight, and this is likely because they are almost entirely cutting out a food group (carbohydrates). Of course, when eliminating foods from the diet, weight will be lost. In addition, the increase in fat and protein consumption can promote satiety (feeling of fullness), which in turn can help support weight loss. Research has shown that ketosis can impact our appetite hormones, ultimately causing the suppression of appetite. This suppression is likely why people “dieting” enjoy the keto diet, as they are not feeling deprived or starved. Other research has shown significant reductions in body fat and weight in the short term (3–6 months), but long-term weight-loss research is lacking.
Bottom line: The keto diet might lead to weight loss in the short term, but is this approach to eating sustainable in the long term? In fact, many studies have shown weight losses to be unmaintainable at 12 months when following an extremely low–carb diet.
Although the keto diet has some positive impacts on health and weight loss, there are also a lot of risk and potential side effects. During the initial transition to the keto diet, there are side effects known as the “keto flu,” which include nausea, dizziness, irritability, poor exercise performance, and fatigue. These feelings typically last for a few days. In addition, ketosis changes the water/mineral balance in your body, which often puts people are risk of mineral deficiencies and in need of supplements to compensate for their losses. This is particularly important when we think of bone health.
Other common side effects include bad breath (from the production of acetone), constipation (because the diet is lacking whole grains and fibre), and potential influence on cholesterol levels over time. In addition, the transition into and off a keto diet can be hard on the body, so it’s important to ensure you are doing so in a safe manner. Be sure to connect with your trusted health-care provider during this transition phase.
What About My Muscle?
Carbs play an important role in exercise performance and muscle growth, especially when it comes to high-intensity exercise (for example in the case of elite athletes). Carbs help promote muscle recovery, produce insulin (which supports nutrient absorption), and reduce muscle breakdown. When it comes to supporting muscle growth and strength, a moderate-carb diet appears to be best.
Do the Benefits Outweigh the Risk?
This really depends on the person. I am personally not an advocate for almost completely cutting out a food group because:
- 1. Our bodies like using carbs for energy; and
- 2. It’s very hard to sustain this eating pattern over time.
I believe that finding a diet that works for your lifestyle (that can be followed in the long term) is the true key to health (and even weight loss). I also believe in balance, which includes enjoying carbohydrates too! Although the keto diet may help you lose weight initially, can you sustain it—or do you want to?
- Saslow, L.R., et al. “An online intervention comparing a very low-carbohydrate ketogenic diet and lifestyle recommendations versus a plate method diet in overweight individuals with type 2 diabetes: A randomized controlled trial.” Journal of Medical Internet Research, Vol. 19, No. 2 (2017): e36.
- Westman, E.C., et al. “The effect of a low-carbohydrate, ketogenic diet versus a low-glycemic index diet on glycemic control in type 2 diabetes mellitus.” Nutrition & Metabolism, Vol. 5 (2008): 36.
- Gibson, A.A., et al. “Do ketogenic diets really suppress appetite? A systematic review and meta‐analysis.” Obesity Reviews, Vol. 16, No. 1 (2015): 64–76.
- Brehm, B.J., et al. “A randomized trial comparing a very low carbohydrate diet and a calorie-restricted low fat diet on body weight and cardiovascular risk factors in healthy women.” The Journal of Clinical Endocrinology and Metabolism, Vol. 88, No. 4 (2003): 1617–1623.
A registered dietician with the College of Dietitians
of Ontario, personal trainer and family food expert
who specializes in women and child nutrition and
fitness, she loves helping families get healthy