If you’re stuck in the “carbs are fattening” mentality, it’s time to reconsider. An important study by National Institutes of Health researchers compared low-carb and low-fat diets among overweight volunteers. Both diets had the same number of calories, but under direct supervision over four weeks, the low-fat diet resulted in roughly twice as much body fat loss compared to the low-carb diet.
Carbohydrates are not inherently “good” or “bad.” Many nutritious foods, including fruits and vegetables, contain both simple and complex carbohydrates. While it’s easy to label complex carbs as “good” and simple carbs as “bad,” this is a misunderstanding. The real culprits are refined carbs, which have given carbohydrates a bad reputation overall.
What Exactly Are Carbohydrates?
Carbohydrates are the body’s primary fuel source. They are broken down chemically and provide energy usable by all tissues. Key organs like the brain, kidneys, muscles, and heart rely mainly on specific types of carbohydrates. Carbs also help synthesize nonessential amino acids.
Typical sources include fruits, vegetables, nuts, grains, milk, seeds, and legumes. The three main types are:
- Sugars: Simple carbs found in fruits, milk, and processed foods.
- Starches: Complex carbs in grains, potatoes, and legumes.
- Fiber: Indigestible carbs in whole grains, fruits, and vegetables that aid digestion.
The Myth of Low-Carb Diets
Low-carb (often high-protein) diets are based on the belief that all carbohydrates cause weight gain, but numerous studies suggest otherwise. As Linda Van Horn, PhD, lead researcher at Northwestern University, explains: “Without exception, a high-complex-carbohydrate, high-vegetable-protein diet is associated with low body mass. High-protein diets were associated with higher body weight.”
Van Horn elaborates: “The point we are trying to make is that what we consider desirable carbohydrates are complex, or high-fiber-containing carbohydrates: whole grains, fruits, and vegetables—not doughnuts or even polished rice. We are looking at legumes and vegetables that offer fiber as well as protein. We’re not talking about refined carbohydrates, commonly known as sugar.”
While refined carbohydrates can increase insulin levels and contribute to obesity—especially when paired with fats (common in Western diets and increasingly in modernized Eastern ones)—the carbs in whole foods often have the opposite effect. In other words, the issue isn’t with “carbs” broadly, but with processed foods. Blanket criticism of all carbohydrates overlooks their natural, beneficial role.
Diet Comparisons: Low-Fat vs. Low-Carb
Low-fat diets are more effective for weight loss than low-carb or high-protein diets. Furthermore, the only diet with scientific evidence for reversing heart disease, early-stage prostate cancer, and even aspects of aging (by extending telomeres) is a whole-food, plant-based one that’s low in both fat and refined carbohydrates.
To date, no randomized controlled trial has shown that a high-fat, low-carbohydrate diet can reverse heart disease—in fact, it often worsens the condition. One study found that following a high-fat, low-carb diet was linked to a 32% higher risk of premature death from any cause and a 50% greater risk of cardiovascular mortality[1].
Typical low-carb ketogenic diets, like Atkins, have been found to impair artery function[2]. Over time, blood flow to the heart muscle itself diminishes on high-protein, low-carb diets[3]. Heart disease tends to progress on standard weight-loss diets and actively worsens on low-carb ones, but it can be reversed with a healthy plant-based approach.
The Risks of Unhealthy Weight Loss
You can lose weight in many ways that aren’t good for you—like smoking cigarettes, getting tuberculosis, or undergoing chemotherapy. The purpose of weight loss isn’t to make it easier for the pallbearers; it’s to improve health.
Diets often increase the risk of not meeting essential nutrient requirements. Ketogenic diets, for instance, are so nutritionally empty that you’d need to consume over 27,000+ calories a day [4]to get all your vitamins and minerals. Choosing a healthier diet is far easier than extreme measures like drinking 3 kg of ghee.
Evidence shows people can lose weight on high-protein, low-carb diets, but you shouldn’t mortgage your long-term health for short-term results.
Practical Advice for Better Carb Choices
If, at all, you’re eating some “bad” carbs, mix them with good ones and high-fiber foods. This mitigates rapid absorption into your bloodstream, keeps blood sugar stable, and avoids insulin surges.
Ultimately, it’s important to eat less fat, less animal protein, fewer refined carbohydrates, and as much whole-food, plant-based foods as possible.
P.S. We’ll explore healthy and sustainable approaches to weight loss in greater detail another time.
[1] https://www.cardiosmart.org/news/2019/10/questioning-the-long-term-safety-of-the-high-fat-low-carb-diet
[2] https://pubmed.ncbi.nlm.nih.gov/11022871/
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