I hadn't known about this study until this week - and wow, it's an eye-opener! It paints a very clear picture that we've known for decades just how effective a low-carb diet is, but have been fed a steady diet of low-fat lies as our nation has grown overweight and obese over the last three decades.
The study, Effect of body composition and other parameters in obese young men of carbohydrate level of reduction diet, was published in the American Journal of Clinical Nutrition in March of 1971. It was designed to investigate the weight loss effect of diet with varying carbohydrate content and specifically kept protein intake and calories the same in those following the diets. By today's standards for study design, this one is good since it controlled both calories and protein intake to have an accurate measure of how carbohydrate influenced weight loss, if at all.
The limitation, which must be stated up front, is that this was a small study on just eight collage aged men.
For three weeks they were fed a "maintenance diet" of, get this, 3000-calories a day, with 115g of protein, 425g of carbohydrate and 160g of fat (macronutrient percents - protein 12.8%, carbohydrate 47.2%, fat 40% - fairly close to the "norm" in 1971). Once this maintenance period ended, three groups consumed differing amounts of carbohydrate (and of course, fat). The diet compositions of each group, each consuming 1800-calories per day, were:
- Group A = 115g protein (25.5%), 104g carb (23.1%), 51.4g fat (51.4%)
- Group B = 115g protein (25.6%), 60g carb (13.3%), 122g fat (61.1%)
- Group C = 115g protein (25.5%), 30g carb (6.7%), 135.5g fat (67.8%)
With each group having a similar 3000-calorie a day maintenance requirement, then reduced to 1800-calories a day, or a calorie restriction of 1200-calories a day, who lost more weight?
For those committed to the calorie theory - that is "calories in = calories out" all three groups should have had similar weight loss, no?
Let's see what happened...
- Group A lost 11.5kg (25.3 pounds)
- Group B lost 12.78kg (28.11 pounds)
- Group C lost 16.18kg (35.6 pounds)
Are you scratching your head yet?
Wait a minute, you may be tempted to say....that's not possible!
The researchers added another nugget in the paper - they didn't control for energy expenditure and when they calculated this, it seems that Group A had increased their energy use to 3400-calories a day, Group B upped theirs to just 3300-calories a day, and Group C used 3,400-calories a day.
Based on this additional piece of data, how much should each group have lost?
This is easy to figure out - they ate 1800 calories a day and burned either 3,300 or 3,400 per day, making a calorie deficit of 1500-1600 calories a day. They did this over 9-weeks, so their total deficit was 63 days x 1500-1600 calories a day = 94,500 or 100,800 calories, then divided by 3,500 calories that is a pound of weight loss = 27-pounds or 28.8 pounds.
- Group A should have lost 28.8-pounds and lost 25.3-pounds
- Group B should have lost 27-pounds and lost 28.11-pounds
- Groups C should have lost 28.8-pounds and lost 35.6-pounds
The researchers were intrigued and did something important - they measured how much of that weight loss was fat. And, this is where things get more interesting...
- Group A - 75% of their weight loss was fat
- Group B - 84% of their weight loss was fat
- Group C - 95% of their weight loss was fat
Still with me?
In the discussion section of the paper, the researchers basically concluded that "no adequate explanation can be offered" as to why weight loss and fat loss differed so dramatically between the groups. They continued that even after accounting for energy expenditure differences, that didn't explain the differences seen in weight loss.
The researchers remarked in their conclusions that "Weight loss, fat loss, and percent of weight loss as fat appeared to be inversely related to the level of carbohydrate in the isocaloric, isoprotein diets. No adequate explanation can be given for weight loss differences."
Here we are, some 35-years later - as a nation fatter than ever before - and still listening to the 'experts' tell us that carbohydrate restricted diets offer no benefit for weight loss and that restricting fat in our diets is the way to lose weight.
We have a very clear picture of what a calorie restricted, low-fat diet does after seven years - nothing! The WHI Dietary Modification Trial shows this - after seven years on a low-fat diet, the women eating a low-fat (and lower calorie) diet remained overweight at the end of the seven years, losing only about two pounds! Incidentally, this trial was touted as "proof" that low-fat diets don't make you fat! How can anyone miss that this diet kept these women fat?
It's time we - the average, everyday consumers - stand up and say "enough!" to those preaching the low-fat dogma that has no support from the evidence!
In all the years I've spent reviewing the data, I've yet to find just one study that compared a low-carb diet with a low-fat diet that showed better - or healthier - weight loss from a low-fat diet! In fact, every last study I've seen shows - clearly - that a low-carb diet is superior to a low-fat diet for weight loss and more importantly, loss of body fat.
So, are you tired of the low-fat lies yet?