Low-carb diets

Over two-thirds of the adult population and an increasing number of children are considered overweight. Not surprisingly, people turn to low carbohydrate diets (where carb intake is reduced to 50-125 grams daily) as a means to help them reach their weight loss goals. While many have had tremendous success on this diet, criticism of it by official agencies is widespread. Where does the truth lie? Can a low carb diet be improved to make it work better? Is a low carb diet healthy? I’ll weigh in on these issues based on some of the latest research.

Reduce the risk of heart disease

Nearly every study of low carb diets has shown equal or usually greater weight and fat loss compared to low fat diets. However, weight loss is not the only benefit of lowering carbohydrate intake. In fact, the most consistent effects of consuming fewer carbs are decreased risk for diabetes and heart disease. Blood levels of risk factors like triglycerides, HDL cholesterol, glucose and small LDL cholesterol particles consistently improve when carbs are replaced with either protein or fat. These metabolic improvements even occur in the absence of weight loss. In other words, health is improved whether weight loss occurs or not.

Saturated fat: good or bad?

Saturated fat has been demonized more than any other nutrient and is blamed for being a major contributor for just about every major disease. However, many counter-examples exist that shed at least some doubt on the harmful effects of saturated fat. Consider the recent Harvard study that found the highest saturated fat intake also had the least plaque buildup on artery walls.[1] One factor that might explain such paradoxical findings is the background level of carbohydrate intake. The idea is that when carb intake is low, the potential adverse effects of saturated fat are not observed.

In a recent experiment in my laboratory we found that men and women who ate a low carb diet (45g carbs per day) with high saturated fat (36g) actually had two-fold lower amounts of saturated fat in their blood compared to a group consuming a low fat diet (208g carbs and 12g saturated fat) [2]. The concept that resulted from this study was that carbs control the fate of fat.

Eat your veggies for dieting success

A leading researcher in low carb diets surveyed behaviors and attitudes of people following low carb diets.[3] He found people reported a high level of satisfaction and enthusiasm for low carb dieting. The survey identified 1,088 people who lost more than 30 pounds and maintained the weight loss for more than a year. The major dietary change was not an increase in bacon, but rather a large increase in green vegetables and replacement of starch and sugar-containing foods with non-starchy vegetables.

Low-carb diets and ketosis

Ketones are ironically viewed as a negative side effect of low carb diets, when in fact ketones are described by leading scientists as “good medicine” or “super fuels.”[4] Ketones are misunderstood because they are confused with ketoacidosis, which develops in people with uncontrolled diabetes. Increased ketones from a low carb diet are quite different and reflect accelerated fat breakdown. When fat breakdown exceeds the immediate need for fuel, the body temporarily makes ketones that circulate around the bloodstream to be used by cells for energy.

Lose 20 pounds of fat in 12 weeks

Protein supplements fit perfectly into low carb diets and can enhance fat burning and muscle-building effects. This is especially important if you are working out. Preliminary results from a recent experiment in my laboratory provide remarkable insight on how to achieve optimal changes in body composition.

We studied a group of men on either low fat (25% fat) or low carb diets (15% carbs). In addition to restricting carbs, the low carb group consumed a ready-to-drink casein protein shake (160 calories, 35g protein, 2g carbs). They took half a serving before and after their workouts (3 days per week) and one serving on non-training days.

The results were nothing short of extraordinary. Several men lost more than 20 pounds of fat and gained as much as 12 pounds of muscle in just 12 weeks. The combination of carb restriction and timed protein shakes around workouts that included resistance training is profound. A protein shake consisting of whey or whey and casein would likely have produced similar results.

Low carb diets can place an extra demand on branched-chain amino acids (BCAAs) because unlike other amino acids, they are used as fuel. Whey protein is higher in BCAAs than other protein sources and has other unique qualities that make it an excellent complement to a low carb diet.

Supplement with omega-3s

Although eating saturated fat is not all that bad on a low carb diet, it still makes sense to emphasize supplementation with certain types of health-promoting omega-3 fatty acids like those found in fish or flaxseed oil. They help reduce blood fats further and fight inflammation.

Green tea boosts metabolism

Green tea is a great accompaniment to a low carb diet to further augment fat loss. Green tea extract contains several polyphenolic compounds shown to have wide-ranging health effects. In particular, green tea extract has been shown to protect the body’s natural thermogenic hormone, norepinephrine, from being destroyed.

Practical considerations

Low-carb diets receive a fair share of criticism, most of it undeserved. Restricting carbs can play an important role in helping people lose weight and improve overall health. Combining it with weight training is the most effective way to trade fat for muscle. Adding casein or whey protein shakes, omega-3 fats and green tea extract is a perfect way to enhance the effects further.


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