Why Your Low-Carb Diet Might be Sabotaging Your Success

Katie Leahy
Stronger U Coach, RD

As you amazing SU’ers already know, carbohydrates are our body’s main source of energy. Carbohydrates fuel our body with glucose which is converted to energy used to support our brain, kidneys, heart muscles, and central nervous system.

How many forms can one diet take? As many that will sell. The Atkins diet, the keto diet, the bullet proof diet are just a few of many diets that likely come to mind when you hear low carb. Wow, carbs seem pretty important, so why do we hear so much on the urgency to restrict them? Why do carbs get such a bad reputation?

Mostly because not all carbohydrates are created equal, as some offer more nutritionally than others. And our diets, in general, are relatively unbalanced. It is my opinion that the pioneers of low carb were a quick study to the US diet, that it contains too many low quality carbs. A recent study published in The Journal of the American Medical Association showed that Americans are consuming 42 percent of their daily calories from refined carbohydrates. While only 9 percent in high quality carbohydrates such as fruit and whole grains. Please read that again. Naturally then, when the low carb diet swoops in, it instantly reduces that 42 percent of daily calories from refine carbs down to 10%. I am no math genius but that alone creates an instant weight loss for almost anyone. Carbs are easy to target because we know them, we love them, and they make up a large part of our diet.

I do believe a low carb diet has a time and a place. I work with individuals with varying medical diagnosis, nutritional needs in which greatly benefit from both short term and long term low carbohydrate diets. The study of low-carb diets has centered on weight loss in obese and overweight people but frequent usage includes type 2 diabetes, nonalcoholic fatty liver disease, seizure disorders and within the athletic population as an alternative fuel for performance and health.

What is a low carb diet?

  1. A very low carb diet: 21g to 70g per day (Atkins & Keto classify as this)
  2. A moderately low carbohydrate diet: 30 to <40% of kcal as carbohydrate per day. Example, 1500 kcal diet, low carb range would be 112-146g

What it does:

A low-carb diet causes the body to burn stored fat for energy, which targets fat loss. Very low-carbohydrate diets minimize available glucose, the body’s primary and main source of fuel, causing ketone bodies to then become the major source of fuel. Low carb diets focus our attention on getting most calories from fat/protein instead. When carb intake is limited to 20 to 50g per day, Ketosis can occur. As we also know, increasing protein intake can help us stay full for longer, keeping hunger at bay which is a benefit when slashing carbs so dramatically.

Low-Carb Diets aren’t a Cure-All

While low-carb diets are popular in the diet world, there are many things to be aware of about why this style of eating isn’t healthy or sustainable. Here are a handful of the red flags that I notice when researching low-carb diet options:

Universally evidence based

The research is inconsistent. There is no concrete evidence that very low-carb intake always produces metabolic ketoacidosis. Many people following very low carb diets on their own are not actually in ketosis and may not know because they are not checking. Just like anything nutrition related, diet recommendations should not be a one-size-fits-all. Twenty to 50 g of carbs might be too restrictive for some people, but 75 to 90 g may be doable for others and still provide excellent results.

100% Effective or Safe

There’s very little evidence to show that this type of eating is effective or safe long term for anything other than epilepsy. Very low carbohydrate diets can have higher rates of side effects, including constipation, headaches, bad breath, fatigue to name a few while the diet is being followed.

Healthier

A low carb diet’s requirements can lead to missing out on many healthy foods, micronutrients and nutritive value. The high fat content of these diets has potential to lead to consuming an unhealthy amount of saturated fat. When nutrient dense foods are limited and saturated fats are increased, long-term heart health could be compromised. Many individuals are following these diets without regard to food choices. Very low carb diets have been associated with inadequate vitamin/mineral intake, including calcium, potassium, magnesium, B vitamins, and vitamin C. We especially need these nutrients to promote healthy bones.
It is also suggested that when nutrient density is reduced, changes in the gut microbiome can occur. We know good gut health can support a healthy immune system and more.

Sustainable

While some can follow low carb for life, most simply cannot. As we know, when we stop what we’ve been doing, or discontinue behaviors that helped us achieve initial weight loss, it will come right back on. This goes the same for a very low carb diet. Our environment today with eating out, traveling, portions, can make sticking to a very low carb diet extremely challenging to follow long term.

Education

Very low carb diets do not teach us how to eat. Most diets that restrict or omit a food group prevent us from learning and practicing what a balanced way of eating should look like. It teaches many from the get go that carbs are bad and we can do without them. Which has a tendency to promote an all or nothing mentality.

For everyone

Very low-carb or keto diets are not recommended for certain people with:

  • lipid metabolism disorders
    • recent heart attack or stroke
    • women who are pregnant or breast-feeding;
    • kidney or liver disease
    • alcohol or substance abuse
    • eating disorders
    • type 1 diabetes or type 2 diabetes with beta-cell dysfunction/failure; and
    • people with diabetes who take SGLT2 inhibitors (eg, empagliflozin and canagliflozin), because of increased risk of diabetic ketoacidosis

What next?!  

For those who are interested and motivated to follow a very low carb diet, you will have improved sustainability and outcomes by teaming up with a skilled nutrition coach and/or registered dietitian. It is helpful to have a skilled professional by your side walking you through short-term side effects of transitioning into nutritional ketosis, with meal planning, maintaining balance, gut health, reduce gastrointestinal symptoms, and meet vitamin and mineral needs. There are so many factors that go into appropriate management including adequate hydration, carbohydrate threshold, quality of fat sources, maintaining good digestion, promoting gut health, and helping individuals assess if a very low carb diet is right for them.

Action item: I challenge you to get curious this month and see where the majority of your daily carbohydrate intake is coming from. Is it mostly complex carbs or refined carbs?

References

Trends in Dietary Carbohydrate, Protein, and Fat Intake and Diet Quality Among US Adults, 1999-2016. JAMA. 2019;322(12):1178-1187. doi:10.1001/jama.2019.13771

Oh R, Gilani B, Uppaluri KR. Low Carbohydrate Diet. [Updated 2021 Jul 12]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-.  Available from: https://www.ncbi.nlm.nih.gov/books/NBK537084/

Gordon, B.What is the Ketogenic Diet?, Academy of Nutrition and Dietetics. 2019 May. Available from: https://www.eatright.org/health/wellness/fad-diets/what-is-the-ketogenic-diet

2015-2020 Dietary Guidelines for Americans. U.S. Department of Health and Human Services and U.S. Department of Agriculture. https://health.gov/dietaryguidelines/2015/guidelines.

Go to:

https://www.ncbi.nlm.nih.gov/books/NBK537084/

MYTHS- https://www.womenshealthmag.com/weight-loss/a19951161/low-carb-diet-myths/

Go to:

https://www.ncbi.nlm.nih.gov/books/NBK537084/

MYTHS- https://www.womenshealthmag.com/weight-loss/a19951161/low-carb-diet-myths/

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