“Wait, is butter a carb?” – Regina George
Low carb diets have skyrocketed in popularity the past few years (even before Mean Girls came out in 2004 😉). But, what is a low-carb diet? And, why does everyone seem to be following one? This article will get to the nitty gritty science of low carb diets, discuss the pros and cons, and provide an easy beginners guide to low carb dieting.
What are carbohydrates?
Carbohydrates are one of the three main macronutrients (alongside protein and fat). Foods high in carbohydrates include items such as bread, pasta, rice, starchy vegetables, and sweets/desserts.
There are two main types of carbohydrates: simple and complex. Our bodies rapidly absorb simple carbohydrates, and our blood sugar quickly increases. Foods like white rice, potatoes, white sugar, and fruit juice are high in simple carbs. Unless you’re an athlete needing a quick source of energy during a race, we generally want to limit simple carbohydrates. Complex carbohydrates, however, are slowly absorbed and do not increase our blood sugar as quickly. Examples of complex carbohydrates include fiber and starch. Fiber has tons of health benefits including heart disease prevention, improving gut health, and promoting weight loss! Our body will eventually break down all digestible carbohydrates into glucose, which our cells then use for energy.
In general, the U.S. government nutrition guidelines recommend a low fat high carb diet, with up to 65 percent of calories from carbohydrates (1). This would equal about 325 grams of carbohydrates per day on a standard 2,000 calorie diet. To give a little more reference, this is equal to the carbohydrate amount of 7 cups of rice, or almost 9 baked potatoes in one day!! Needless to say, many health experts and organizations are now questioning whether a low fat high carb diet is actually the best recommendation for overall health and disease prevention.
What is a low carb diet?
With the rising rates of diabetes, insulin resistance, and obesity, low carb diets have grown in popularity as a potential diet solution. But, what is considered “low carb”? This is where things get a little tricky. There is no consistent definition for “low carbohydrate diets”. If comparing to the U.S. Dietary Guidelines, then many diets may be considered low carb.
- Paleo diet – This diet is generally considered low carb (under 40 percent of calories) because it restricts many foods high in carbohydrates, like grains.
- Atkins diet – A low carb, high protein diet that restricts carbs to about 5 to 10 percent of calories (depending on your total calorie intake).
- Zone diet – This diet is moderately low in carbohydrates, around 40 percent of calories per day.
- Ketogenic Diet – A low carb, high fat diet that restricts carbs to 5 to 10 percent of total calories.
Although the carbohydrate amounts vary in each of these diets, the overall foods eaten in low carb diets is generally the same:
Eat: meat, fish, eggs, some full-fat dairy, non-starchy vegetables, and oils (olive oil, butter, coconut oil etc.)
Avoid/Limit: grains, bread, pasta, rice, starchy vegetables (potatoes, peas, corn, beans), excessive fruit, and sugar.
What does the research say about low carb diets?
Many cultures around the world have eaten what would be considered a low carb diet for hundreds of years. But, the low carb diet didn’t become “mainstream” until the 1990s. This popularity triggered many new studies to come out about the low carb diet to assess if it actually works. Let’s take a look!
Low carb diets have shown great promise in weight loss studies so far. In fact, three large review studies looking at over 70,000 people found that participants on a low carb diet had significantly decreased body weight and waist circumferences (2-4).
What about a low carb vs. a low fat diet for weight loss? Despite many health organizations previously (and some currently) promoting a low fat high carb diet, many studies show that low carb diets result in more significant weight loss than a low fat diet. One of the largest research reviews looking at a collection of different low carb vs. low fat diets for weight loss concluded (4):
“Health and nutrition guidelines should cease recommending low-fat diets for weight loss given the clear lack of long-term efficacy over other similar intensity dietary interventions”.
How does a low carbohydrate diet help with weight loss?
By reducing carbohydrates in the diet, your body lowers the amount of insulin it produces (5). Insulin is a hormone that has many important jobs in the body, like lowering your blood sugar back to normal after a meal. But, insulin release also causes the body to produce, store, and hold onto fat cells. Through a low carb diet, insulin levels decrease and the body can now burn fat cells for energy! Low carb, high fat diets additionally suppress our hunger hormone, called ghrelin, and may force the body to burn more calories through a concept known as “reduced thermodynamic efficiency” (6,9).
Diabetes and High Cholesterol
Low carb diets are completely challenging the status quo for treating type 2 diabetes and high cholesterol. Many studies show that a low carb, high fat diet significantly lowers triglycerides and total cholesterol amounts (2,3,10). Additionally, low carb diets can significantly increase our “good” HDL cholesterol more effectively than other diets. A common argument against a low carb, high fat diet is that it raises the LDL cholesterol levels. The LDL cholesterol is often referred to as the “bad” cholesterol, because the small, dense LDL particles may increase heart disease risk. However, studies show that a low carb diet does not increase the small, dense LDL particles. Rather, a low carb diet may increase the larger, “fluffy” LDL particles which do not cause the same harmful effect (11, 12).
Since a low carb diet does not raise our blood sugar as much, it is growing into a powerful new tool to treat type 2 diabetes as well. Many studies show a powerful lowering effect on hemoglobin a1c (a lab marker for diabetes) (2,3,10). Additionally, a low carbohydrate, high fat ketogenic diet study showed that 94 percent of participants reduced or completely stopped their insulin medication (13)!
PCOS and Low Carb Diet
Polycystic ovarian syndrome (PCOS) is a hormonal imbalance that affects up to 10 percent of women (14). In PCOS, the body overproduces testosterone which leads to abnormal menstrual cycles, lack of ovulation, and enlarged ovaries. The exact cause of PCOS is unknown. But, experts suspect that factors like genetics, increased male hormone levels, and insulin resistance may play a role (15). This is where a low carb diet comes into play. Low carb diets have shown great success in reversing insulin resistance and treating PCOS by promoting healthy weight loss (16, 17). With PCOS and a low carb diet, insulin levels decrease, which then leads to less testosterone production and more balanced hormones! If a pregnancy is in your future plans, a lower carb diet may help improve fertility, too. One recent research review even concluded (18):
“Reducing carbohydrate load can reduce circulating insulin levels, improve hormonal imbalance, and resume ovulation to improve pregnancy rates compared to usual diet.”
Common mistakes to avoid on the low carb diet.
A low carb diet can be helpful in reducing body weight, blood sugar, and cholesterol levels if done right. But, there’s more to a low carb diet than just “avoiding carbs”. Without proper guidance and/or research, many people make major mistakes on the low carb diet that can sabotage any efforts. We don’t want that to happen to you! Here are a few common mistakes, and what to do instead:
Not increasing healthy fats.
There’s a reason why some people are huge grumps while on a low carb diet – they’re freaking hungry! Any diet that leaves you hungry and miserable is not going to work in the long run. This is where many people go wrong: they don’t increase their fat intake! Baked chicken and broccoli are not going to stick with you for long. Without adequate fat, a 2 day low carb diet will seem like a lifetime. Fat is an extremely important nutrient because it helps keep us full and satisfied. Fat also suppresses our hunger hormone called ghrelin, which means our appetite is more controlled, and we are less miserable (your husband can thank us later) (6).
Here are a few ways to increase fat on a low carb diet:
- Add avocado to your eggs or salads. Use guacamole as a dip for low-carb vegetables, like bell peppers and celery.
- Generously use healthy cooking oils like olive oil, grass-fed butter, coconut oil, or avocado oil. Drizzle onto your vegetables.
- Incorporate nuts and seeds into your meals & snacks.
- Add MCT oil to your coffee.
- Rethink your salad dressings. Avoid low-fat dressings and aim for oil based dressings or higher fat versions like our own delicious ranch dressing recipe.
Not eating enough fiber.
Many carbohydrate foods, like whole grain bread, brown rice, and green peas are good sources of fiber. A common mistake is eliminating these foods without replacing with other high fiber, low carbohydrate foods. Although fiber is technically a complex carbohydrate, it is considered a non-digestible carbohydrate. This means that fiber is not digested or absorbed, so it does not raise our blood sugar like other carbohydrates (7). For this reason, many low carb diets do not “count” fiber in the total carbohydrate number. Women need at least 25 grams of fiber per day, while men need at least 38 grams per day. It’s possible to follow a high fiber, low carbohydrate diet! The best way to meet your fiber requirements on a low carbohydrate diet is to aim for at least 2 cups of non-starchy vegetables per day.
High fiber, low carbohydrate (non-starchy) vegetables:
- Leafy greens (spinach, kale, arugula etc.)
- Bell peppers
- Avocados (technically a fruit, but an awesome low carb, high fat fiber source!)
- Brussels Sprouts
Throw veggies into a breakfast omelet, prep a colorful salad (with avocado or oil dressing) for lunch, or sauté some veggies in grass-fed butter for dinner! Yes, you can eat both veggies AND butter! When eating out on a low carb diet, try to ensure you choose at least 1 side of these non-starchy vegetables to go with your meal.
Not individualizing your carbohydrate amounts.
We all have different bodies. A diet that works for one person, may not work as well for someone else. This is a major downfall of most generalized diets. If a low carb diet sounds like something you’d like to try, consider your exercise regimen, lifestyle, and health history.
For example, athletes competing in strenuous, high-intensity events may require more carbohydrates than a traditional low carb diet may provide (8). Carbohydrates are broken down fast enough to provide a quick source of energy in the form of glucose during these times. Additionally, these athletes may need to replace their glycogen stores (the form of glucose that is stored in the liver) with more carbohydrates after exercise.
Another consideration for low carb diets is medications. Jumping into a low carb diet right away may be dangerous if you are on a medication for diabetes, like insulin. While a low carb diet can be very helpful for conditions, like diabetes, it’s important to talk to your health care provider before making any drastic changes. A registered dietitian, in coordination with your doctor, can help you gradually reduce carbohydrates from your diet in a safer way.
Is a low carb diet right for you?
So far, research is promising for the low carb diet regarding weight loss and treating conditions such as diabetes, PCOS, and high cholesterol. But, as we always say in the 131 Method, there is no ONE diet that works for every person. We all have different bodies, genetics, hormone levels, and lifestyles! While reducing processed carbohydrates like candy, baked goods, and sugary desserts is extremely helpful, some people may feel better (and get better results) at different levels of carbohydrates. Additionally, we must ask ourselves this extremely important question: is it sustainable? If it’s not, we will continue to yo-yo between different diets, quick fixes, and food trends.
The 131 Method helps you find a sustainable, individualized eating program for YOUR body.
Through a process called diet phasing, the 131 Method guides you through various eating patterns, including a lower carbohydrate, higher fat phase. This helps you tailor your own diet for what feels best, and what is sustainable for your body and your life. Diets shouldn’t be one-size-fits-all, and this includes low carb diets!