Let’s start by looking at different types of carbohydrates. There are three different types of carbohydrates: starches, sugar and fiber.
- Starch. Starches include starchy vegetables such as potatoes, peas, and corn as well as beans, lentils, dried peas, black beans, split peas, or grains to name a few.
- Sugar. There are two different types of sugar: natural sugar and added sugar. Natural sugar is found in things like fruit or dairy products which naturally contain sugar, while added sugar is found in candy, cookies, canned fruit in heavy syrup or flavored dairy products such as fruit flavored yogurts.
- Tips: When you are reading an ingredient list for sugar look for words ending in “-ose”. This is a clue to you that it is the name of a natural or added sugar. For example, lactose, fructose, maltose, dextrose, galactose, etc.
- Fiber. Fiber is a form of complex carbohydrate that is not broken down during digestion. Fiber is found in foods such as fruits, vegetables, nuts, seeds, whole grains, beans and legumes. It is recommended that adults consume 25-30 grams of fiber each day. Fiber is important for gastrointestinal (GI) health, may help decrease cholesterol and helps you feel full longer.
The dietary guidelines for Americans recommends that 45-65% of daily calories come from carbohydrates. Carbohydrates are used for energy in the body since glucose is the preferred source of energy for the body, especially the brain. Without adequate carbohydrates, the body will use stored glucose called glycogen for energy. Next, after stored glycogen is depleted, gluconeogenesis will take place which turns non-carbohydrate carbons including amino acids from protein into glucose. When glucose supply is insufficient, the body can also convert fat into usable energy for the body and brain, ketones. The brain cannot use fat in itself as a fuel source, but it can use ketones which are made from fat by the liver as an emergency source of fuel.
Low carbohydrate Ketogenic diet for weight loss?
The ketogenic diet has been used to manage epilepsy for many many years, but recently this diet is growing in popularity for weight loss. This diet is very high fat, moderate protein and very low carbohydrate with daily caloric intakes of 70-80% fat, 10-20% protein and 5-10% carbohydrate. Most people think the keto diet is high in protein but is actually only a moderate protein intake because too much protein intake can actually take your body out of ketosis. To put these percentages into perspective, 5-10% of total calorie intake from carbohydrate each day is approximately 20-50 grams for a 2,000 calorie diet. A turkey sandwich with mayo tomato and lettuce contains approximately 30 grams of carbohydrates (15 grams per slice of bread and ~1 gram from the tomato slice). So to stay on a true ketogenic diet you would need to eliminate most fruits, breads, pastas, milk, yogurt, and desserts (15 grams of carbohydrate= 1 slice of bread or 1 small apple with skin or ⅓ cup pasta/rice or ½ cup mashed potato or ⅓ cup sweet potato or 1 cup milk).
When someone decides to start the ketogenic diet it will take about 3-4 days for ketosis to kick in which is often not an enjoyable process as it has earned the name “keto flu”. Some symptoms of “keto flu” can be headache, foggy brain, fatigue, irritability, nausea, difficulty sleeping or constipation to name a few. Research has proven the keto diet to be effective in managing epilepsy but more and more people are using this diet (or low-carbohydrate diets) as a way to lose weight. So here are some research articles on following a low carb/keto diet for weight loss.
Research
A 12 week study in 2018 assessed a ‘healthy’ low fat diet vs ‘healthy low carb diet’. 609 participants reduced their fat or carbohydrate intake (depending on which group they were in) to 20g/day for the first eight weeks. After the eight weeks, participants were able to introduce more fat/carbs back into their diet at 5-15grams/week until they felt they reached the lowest intake level that could be maintained long-term. After 12 months, carbohydrate intake for the low carbohydrate group was up to 30% calories from carbohydrates (150g for a 2,000 calorie diet). So we can see that the low carbohydrate group was not able to maintain the very low 20 gram carbohydrate intake long term. Weight changes were not remarkably different between the two groups. Both diets improved lipid profiles, lowered blood pressure, insulin, and glucose levels, except LDL cholesterol increased in participants on the low carbohydrate diet. All in all, we can learn from this article that low fat and low carbohydrate diets resulted in the same amount of weight loss and participants were unable to maintain a very low carbohydrate intake (20grams/day) long term.
A meta analysis from 2013 collected studies that compared very low carbohydrate ketogenic diet to a low fat diet to look at long term weight loss. Results showed the very low carbohydrate group had a greater reduction in weight loss compared to the low fat group, although when compared to studies that assessed long-term lifestyle interventions the amount of weight loss was not remarkable. It is important to note that although there was a reduction in weight for the very low carbohydrate group, by the end of the follow-up period in many of the studies, participant carbohydrate consumption had increased. This again shows us that participants were unable to maintain the very low carbohydrate diet plan long-term.
What we see in both studies is that the low carbohydrate diet was not sustainable long term. If you are looking to improve your eating habits and experience weight loss, it is very important that the changes you make are sustainable, otherwise you might find yourself “yo-yo”ing back into your old eating habits. Although participants lost weight, was this weight loss due to the decrease in carbohydrate intake? Or was it an increase in mindfulness of what they were eating? Or perhaps was their calorie intake decreased compared to their usual intake? Further research still needs to be conducted on the long term effects of following a low carbohydrate diet for weight loss.
Considerations for a low carbohydrate diet
If you are considering cutting carbohydrates keep in mind that foods high in carbohydrates such as fruit, beans, legumes and whole grains are also high in fiber. When you cut back on carbohydrates you also cut back on many fiber-rich foods. As I mentioned previously, fiber is important for GI health, it helps you feel full longer, may play a role in decreasing cholesterol levels and improving glucose levels. So, fiber is not something we necessarily want to skimp out on for a few reasons. Like I said previously, dietary recommendations for daily fiber intake is ~25-30grams/day but many people do not consume this much. To put this into perspective, ½ cup pinto beans is ~8 grams of fiber, 1 medium apple with skin has ~4 grams, ½ cup cooked navy beans ~10 grams, and 1 medium pear with skin has about ~6 grams. In addition to fiber, cutting carbohydrates also decreases consumption of important vitamins, minerals and antioxidants found in fruit, vegetables, whole grains, legumes, and dairy.
I also want to take a brief moment to discuss the importance of setting a good example when it comes to relationship with food. Children and young adults are watching your eating habits and are taking note. They see you not eating that banana because it is “too high in sugar” or passing on the spaghetti for dinner because it has “too many carbs”. We need to be aware of the relationship with food that we show to the people around us. They are learning from you. They see you counting calories or carbohydrates. They hear you saying “this is healthy” or “that is unhealthy”. They hear you shaming your body and it impacts them just as much as it impacts you.
Following restrictive diets such as the ketogenic diet can be very difficult for individuals in more ways than one. Eating is not only something we do to stay alive, but it is also a social activity and strict rules can make it difficult to enjoy social gatherings with your friends and family. It can be challenging to enjoy a girls night out or watch the game with the guys. Not only do strict diet rules make social events difficult, it can add an unnecessary layer of stress as you work on sticking to your diet rules. Food brings many people together and strict diet restrictions can be harmful in social, emotional and physical ways.
So What's the Verdict?
Long story short, carbohydrates are our friend. They provide our bodies with energy, fiber, vitamins and minerals. Complex carbohydrates found in fruits, whole grain products, legumes etc are important for overall health. Let’s start shifting our view of carbohydrates. It is ok to still enjoy tasty sweet treats such as ice cream, cookies or candy but we balance out these sweet treats with complex carbohydrates, lean/plant based protein sources, vegetables and healthy fats. So let’s end the trend of labeling foods as “good” or “bad”. There is a place for every food in your diet so enjoy food, including those carbohydrates, your body will thank you.
Any changes you make to your eating habits should be sustainable long-term and maintain a healthy relationship with food along the way. Cutting carbohydrates is neither sustainable or portraying a healthy relationship with food. A healthy relationship includes avoiding restrictive eating/binge eating patterns, not obsessing over rules for what you can or cannot eat, eating all food groups, and not labeling foods as “good” or “bad”.