Low carb diets have been popular on and off since the dawn of the Atkins fame.
What exactly defines low carb? Does eating this way actually help with weight loss? Are there any other health benefits (or risks) to eating fewer carbs?
There is a HUGE variation in how people define “low carb.” Let’s first explore …
What is a carb?
A carb, or carbohydrate, is one of your three main macronutrients. Carbs, along with protein and fat, are needed for your optimal health in quantities larger than vitamins and minerals which are micronutrients.
Carbohydrates are plant food. So, while many know that “carbs” include grain products (like flours, breads, pastas, crackers, bagels, muffins and whatnot), they often don’t understand that carbs also include all fruit and vegetables.
Carbohydrates are essential for your body’s overall operating system. Without them, our bodies would fail. They contain:
Sugars are the smallest carb molecule. There are many different kinds of sugars, beyond the well-known table sugar (sucrose) or fruit sugar (fructose). When you look at packaged food, anything that ends in “ose” or “extrin” are also sugar molecules. All cells in your body need sugar to function. So does your brain.
Starches are longer chains of many sugars bound together. Starches are broken down by your digestive enzymes into sugars. These sugars are then absorbed and metabolized in much the same way as if you ate sugar itself. Some starch also has the added benefit of being a food source for your microbiome – the bacteria that help regulate your immune system, found in your digestive tract.
Fibre is also a long chain of sugars, but these are not broken down by your digestive enzymes. Fibre passes through your system, also feeds your friendly gut bacteria, and then takes food waste out the other end. I often explain that eating fibre is the equivalent of having a shower – you are scrubbing and cleaning your insides.
You wouldn’t go days without showering, right? Hopefully? It’s the same thing for your gut – you need to clean it up.
Because fibre isn't digested like sugars and starches, it's often excluded from the carb calculation.
How we metabolize carbs
When you eat carbs, your body absorbs the broken-down sugar into your blood, thus raising your blood sugar. Depending on how high and fast your blood sugar rises, your body may release insulin to tell your cells to absorb that sugar out of the blood for immediate energy use or to store in fat cells for use later on.
But, your body is a bit more complicated than that!
Low carb for weight loss?
A few studies recently put low carb diets head-to-head against low-fat diets for weight loss.
Guess what they found?
There isn't one universal definition of low carb.
It's more difficult for people to stick to low carb diets than low-fat diets.
Both diets work for some people, and neither one is overwhelmingly better for straight-up weight loss than the other. However, I have issues with a low-fat approach for overall health! The right type of fat is essential for brain health, heart health and hormonal health. PLUS fat adds flavour, which helps with satiety.
The number of calories people eat is still considered a huge factor when it comes to weight loss success - more than whether the calories are from carbs or fat.
Starchy carbs are essential for thyroid health. Cutting starch back too much could undermine your weight loss goals if you have an underlying thyroid issue (your thyroid rules your metabolism).
How many carbs is low carb?
There isn't one single definition.
The average American eats about 300 g of carbs per day. Some people consider eating under 250 g of carbs per day to be the first threshold of a low carb diet, however, that's really not that low in carbs. BUT if you’re new to reducing carbs, this level is easy to maintain and a good start.
Taking that a step further, eating less than 150 g per day of carbs is considered a typical low carb diet.
On the extreme side, eating less than 50 g of carbs per day is considered to be very low carb - it falls under the ketogenic diet range. Eating so few carbs can actually change your metabolism into a ketogenic state. Eating this way can be difficult for many people to maintain.
Other health benefits of low carb diets
Low carb diets have the benefit of preserving muscle mass during weight loss. They can also improve heart health biomarkers like cholesterol and triglyceride levels.
Eating fewer carbs can also improve how your body manages those carbs in terms of insulin and fasting blood sugar levels.
There can definitely be some non-weight-loss health benefits to eating fewer carbs!
I believe a good first-step is simply reducing the number of grain products you consume on a daily basis and replace them with fruits and vegetables.
Ounce per ounce, fruits and vegetables hold more nutrition than grains due to their vitamins/mineral content. While they may be same in fibre content, the nutrient density of fruit/veg delivers more benefits to the body AND you still get the “sugars” and “starches” your body needs to function.
Eating a low carb diet can be healthy, as long as it contains enough of all the essential nutrients. Some people may lose weight eating fewer carbs, and others won’t.
Low carb diets can help to improve how the body manages blood lipids and blood sugar, so it can be a healthy choice for some people.
As with most things in nutrition, there isn't a one size fits all rule. Low carb diets can be a good choice for many people, but it's not the magic bullet that some people claim