The Surprising Truth About Low-Carb and Keto Diets

May 16, 2024

By Keith Herman

In my last blog, I explained why portion control is not an effective way to lose weight and keep it off. In this blog I discuss why low-carb and keto diets are not effective in the long-term, for most people.

Robert Atkins, a cardiologist, popularized the low-carb diet in the 1960s.  More recently, the diet has been promoted by Gary Taubes and others, and sometimes rebranded as a “keto diet.” The theory behind these diets is that eating too many carbohydrates leads to blood sugar imbalances and weight gain. Promoters of low-carb diets seem to believe you can eat as many calories as you want and not gain weight – if you just limit your carbs to some magical number (often less than 20 to 60 grams per day).

The truth is that many high-carb foods are ultra-processed junk, and we would all be better off avoiding them. High-carb junk foods include mass produced potato chips, crackers, bread products, cookies, cakes, pies, bakery goods, desserts, pasta, and others.

Many people lose weight when they go on a low-carb diet. If you were previously eating typical high-carb junk foods and then you completely cut them out, I don’t know how you wouldn’t lose weight. When people go on a low-carb diet, they must meticulously track their food intake and count how many grams of carbohydrates they consume. For a typical American, this may be the first time they pay close attention to what they eat. Anyone who cuts ultra-processed junk food from their diet and begins to pay close attention to their food choices will lose weight.

But the weight loss has nothing to do with the number of carbs you consume or your blood sugar. When you become a mindful eater and pay attention to your food choices, you typically consume less calories. Weight loss is not a function of carbs, blood sugar, or insulin. Weight loss is the result of burning more calories than your body absorbs from the foods and beverages you consume. This is called a calorie deficit. You can create a calorie deficit, and lose weight, by limiting carbs, fat, or protein.

The best way to create a calorie deficit is to cut out ultra-processed foods (whether they are low-carb or high-carb doesn’t matter) and eat more fruit, vegetables, intact whole grains, and legumes. You can eat a large amount of these foods and feel satisfied with less calories. This is because plant foods generally have less calories per weight than ultra-processed and animal foods. And by the way, eating more whole plant foods also decreases the risk of heart disease, cancer, diabetes, and Alzheimer’s disease. Unfortunately, most people who follow a low-carb diet end up eating more saturated fat in the form of animal foods, such as fatty cuts of meat and full fat dairy. Contrary to what you may read on the internet, this diet is not health promoting.

In a tightly controlled 2021 study, a low-carb animal-based keto diet was tested against a high-carb plant-based diet. The participants were given 5,000 calories of food and snacks each day and told to eat as much as they wanted. They were also told it was not a weight loss study and that they should not be trying to lose weight.  The high-carb plant-based diet resulted in more fat loss because they averaged 689 fewer calories per day than those on the low-carb keto diet. LDL (bad) cholesterol went down an average of twenty-three points on the plant-based diet but went up four and a half points on the keto diet.

Sustainable, long-term weight loss is the result of eating more whole plant foods, reducing ultra-processed junk, and utilizing one or more of the Hidden Laws of Habit Change.

In my next blog, I explain the misconception about low-fat diets.

Download the Hidden Laws of Habit Change for free.



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