Why Low-Carb Ketogenic Diets Don’t Work

Lately, there is a low-carbohydrate craze that has perpetuated a belief that carbohydrate is responsible for pretty much every dietary-related health issue known to humans. People are jumping on this hype train, with the hope that by avoiding carbs and consuming meat and other fatty products, they will feel better and lose weight. But hey, don’t be fooled by those videos and so many books, avoiding carbs is not the key to lose weight or to be healthy.

This carb-ophobia has spread mainly by people like Dr. Jason Fung and the one and only, Gary Taubes. And of course, by anyone else who wants quick bucks or more views. You want to make money easily? Just write a few books about low-carb, rehearsing everything is on the other books, put and a few recipes there and you are done.

But what is no one says is that the meat consumption has been linked to diabetes and insulin resistance [1, 2], the two diseases you are trying to avoid in first place, by reducing carbs and consuming more and more animal fat, in order to cover your caloric needs. Funny, isn’t it?

And what is more interesting? That people are eating animal protein in order to keep their blood sugar low, while meat increases insulin levels as much as pure table sugar [3, 4]. But they are keep saying that we are somehow programmed to eat meat and dairy, but the are not saying that dairy causes cancer and other deceases too [5, 6, 7, 8, 9].

In their books, they are promoting the belief that reducing carbohydrate intake is the key to lose fat and stay lean. But this is not always the key, because to lose body fat, is far more complex than simply eliminating carbohydrate from your diet [10]. Carbohydrate should be an integral part of your dietary regimen and I will explain the reasons below.

Without carbohydrates as an energy source, your body enters into a metabolic state in which is forced to increase production of fat metabolites known as ketone bodies (due to an increased demand for fatty acid oxidation) as a substitute for carb fuel, so it breaks down fats and proteins.

This drop in protein levels can lead to muscle wasting and impaired immune function, making you more vulnerable to infection [11, 12]. And in order to protect your muscles, you have to eat more -animal- protein [13], which makes things even worse, as it already noted (see studies above).

Low Carbs And Blood Sugar

When you are cutting carbs, and/or fasting in order to lose weight, your blood sugar starts to drop. As a result, your body makes extra cortisol to raise it back up again [14]. Extra cortisol means body weight gain, poor sleep, and hormone unbalances [15] (more on that later). But this is not the only problem.

Low Carbs And Ketosis

While you are keep following this type of diet, the body increases the mobilization of fatty acids for fuel and increases liver synthesis of ketone bodies, resulting in ketosis. Ketones serve as fuel alternative and promoters of ketogenic diets promise maximum fat loss when ketosis is induced. What is seemingly great in theory, however, does not always work in reality.

For start, long-term ketosis can lead to a fall in bone density [16], kidney disease [17], kidney stones [18] and insulin resistance [19, 20].

During ketosis, and because ketone bodies are acidic, blood pH declines [21]. In order the body to deal with the acidifying effect of ketosis, it will secrete insulin, as a desperate attempt to prevent further acidosis. Insulin will inhibit lipolysis and thus suppress ketosis, and as a result fat loss is suppressed. This is the reason why diabetic ketoacidosis arises, because of a lack of insulin in the body [22].

So, advanced ketosis inhibits fat loss and increases insulin levels [23, 24, 25], and thus the ketogenic diet’s quest of reaching ketosis clearly fails to induce fat loss.

Low Carbs and Metabolic Rate

Ketogenic diets are affecting the body’s metabolic rate. Chronic extreme carb restrictions adversely reduce cellular adenosine triphosphate, thus impairing thyroid hormone activation [26, 27].

Low thyroid activity

If you are exercising while you are on a low-carb diet, this can drastically reduce your thyroid activity. Low thyroid activity is associated with:

  • Increased cortisol output
  • Decreased testosterone
  • Impaired mood and cognitive function
  • Muscle catabolism
  • Lack of strength
  • Suppressed immune function
  • Sensitivity to cold
  • Fat gain

From the thyroid hormones, one is the most active and most important for blood glucose management and proper metabolic function, T3 [28]. Low T3 levers are the reason why people are constantly cold and sluggish.

T3 is very sensitive to calorie and carbohydrate intake, along with reverse T3 ((rT3) Reverse T3 inhibits T3). When calories and carbs are too low, your T3 levels drops [29]. That is, for the body, low carbs equals with low calories intake, so replacement of dietary carbohydrate with fat results in changes typical of starvation [30, 31].

The solution? Getting enough carbs. By eating enough carbs, you can lower reverse T3 (the hormone blocking the important work of T3) and raise T3. And how many carbs are enough? Well, plenty of them. In a study, they found that by reducing carbohydrates from 409 g to 202 g and then to 104 g significantly reduced serum T3 levels (from 91 to 86 to 69 ng/dL respectively) [32].

Low Carbs, Training And Fasting

One of the people’s most favorite advices, is to exercising while fasting, so to force your body to burn more fat. And of course, they keep telling people to go to the gym hungry or to drink just coffee pre-workout, in order to maximize the fat-burning effects.

But this is the worst advice to hear. Studies show that training in a glycogen-depleted state has a catabolic effect on muscle [33]. Low glycogen levels alter cellular signaling pathways, impairing protein synthesis and reducing the effectiveness of the genes responsible for regulating muscle growth. The take-away message is that you simply won’t maximize muscle development without including a healthy amount of carbohydrate in your diet [34, 35].

How Many Carbohydrates Do I Need?

With adequate nutrition, you can repair and improve muscle size and/or quality. It is important to meet your energy demands and replenish glycogen stores when you are trying to build muscle. Aim to consume 1.5 to 2 g of carbohydrate per pound of body weight each day. For muscle-building purposes, most people seem to do best consuming 2 to 3 g of carbohydrate per pound of body weight. The American College of Sports Medicine recommends for athletes to consume anywhere from 2.7 to 4.5 g of carbohydrate per pound of body weight, depending on the activity [36].

Those who are insulin insensitive, may require a lower intake to avoid fat storage. You can experiment different amounts to see what works best for you, but you can start by consuming as low as 1 gram per pound of body weight per day.

Which Type Of Carbs?

All types of carbohydrate are not created equal. The best type of carbohydrate are the whole grains, nutrient-dense carbohydrate foods, which are insulin friendly and they supply your body with essential compounds that enhance metabolic function. Vitamins and minerals in these foods can help the body in burning fat [37], while their antioxidants keep cells functioning optimally.

Avoid processed carbs. This type of carbohydrate are basically empty calories, they contribute nothing to biological function and send blood sugar levels sky high and excessive consumption of these foods can result to exacerbated insulin resistance.

On the other hand, brown starches are not processed and thus maintain their nutrient density. They digest slowly, allowing glucose to enter the bloodstream in a time-released fashion, keeping insulin stable avoiding the potential for excess fat storage.

Final Thoughts

Low-carb ketogenic diets are very popular these days. People who suffer from insulin resistance, may benefit from low-carb diets adjusted to their individual needs [38], but completely avoiding carbs is not the solution.

High saturated fat and low starch and fibre are associated with insulin resistance in animals [39] and humans [40] and may predispose to the development of diabetes [41].

So you can’t just cutting carbs and hoping that this will help you reduce the risk to the development of diabetes [42]. Neither can help you to stay lean and healthy [43, 44].

So, the attempt to reach a metabolic state of ketosis for losing fat (such as with extreme high-fat, no-carb diets), to cure diabetes or insulin resistance, is misleading, ill-advised, and counter-effective.

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