Medical myth: Cutting carbs is the best way to lose weight

August 27, 2012 by Gary Sacks, The Conversation
Medical myth: Cutting carbs is the best way to lose weight
A calorie is a calorie, no matter what type of food it comes from: Mrs Magic.

There seems to be an endless number of fad diets and "golden rules" for weight loss. One of the most popular of these rules is that cutting carbohydrates (carbs) is the best way to lose weight.

The most famous low-carb is the , first developed in the 1970s. The Atkins diet recommends limiting foods high in , such as bread, pasta and rice. Carbs are replaced with foods containing a higher percentage of proteins and fats (meat, poultry, fish, eggs and cheese) and other low-carb foods (most vegetables).

But what does the evidence show us about whether low-carb diets really are best for ?

Theoretically, a "calorie is a calorie" and it doesn't matter what types of food the calories come from. Accordingly, all reduced-energy (calorie) diets should lead to equivalent weight loss.

However, some studies have reported that low-carb diets lead to greater weight loss than other types of diets, at least in the short-term. So, what are the possible explanations for these results, and can we rely on them?

1) Changes in body composition

Energy is stored in the body as protein, fat, and , which is a form of . If there is an imbalance between how many of these nutrients are ingested (through the food that is eaten) and how many are used by the body for every day functions, will change.

In turn, this will affect body weight because of the different impact that the relative amounts of stored protein, fat and carbohydrates have on body weight.

However, the vast majority of studies in which they've measured very accurately (that is, they've locked people in a room and measured exactly what they've eaten for several days), show absolutely no difference in weight loss based on the composition of the diet. and high-carb diets resulted in the same weight loss.

This indicates that, in the short-term at least, the human body is a superb regulator of the type of energy it uses, and whether the diet is low-carb or high-carb probably won't make much of a difference to the amount of weight lost.

2) Changes in metabolic rate

The body's metabolic rate (the amount of energy expended by the body in a given time) is dependent on the composition of the diet. Consumption of protein, for example, is known to result in a larger increase in for several hours after a meal compared with the consumption of fat or carbs.

But the overall effect of diet composition on total energy expenditure is relatively small. As a result, the assumption that a "calorie is a calorie" is probably a reasonable estimation as far as energy expenditure is concerned.

3) Changes in hunger levels and satiety

Some diets can lead to reduced hunger, improved satiety (feeling full), and can be easier to stick to than others. There is an enormous amount of research on this.

The problem is that it's extremely difficult to accurately measure what people are eating over extended time periods. People rarely stick to their diets for more than just a few weeks, making it almost impossible to adequately compare the effects of different diets.

And so, is cutting carbs the best way to lose weight?

Maybe, but there's not really good evidence supporting it. All diets with similar calorie content have a similar effect on weight loss in the short-term. This is because the body adapts rapidly to changes in relative protein, fat and carbohydrate intake levels.

The truth is that losing and keeping it off in the long-term is difficult. It requires permanent changes to the number of calories you eat each day.

Perhaps the best dietary advice comes from Michael Pollan when he says, "Eat food. Not too much. Mostly plants."

Explore further: Calories, not protein or carbs, are key to weight loss for people with diabetes

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Shootist
not rated yet Aug 27, 2012
At age 47 I started a 4000 to 5000 calories a day, low carb diet, that lasted for 16 months.

Bacon, eggs, cheeses of every kind, beef, salami, pepperoni, prosciutto, pork chops, ham, bacon and eggs and cheese, leaf lettuce and green beans with bacon and 25 grams of almonds a day. I lost 160 pounds. I was never hungry. My cholesterol levels lowered (though they had never been high). My blood pressure went to normal. I felt good.

Did I mention I was never hungry?

Did I mention that there is nothing that bacon cannot do?

8 years later I am still 90 pounds off my high of 360.

Of course, your mileage may vary.

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