So far, we’ve explored data which conclude low-carb diets aren’t more effective than high-carb diets at achieving maximum fat loss or better health. At best, one could argue pros and cons between the two opposing diet methods, but a growing amount of research points to a clear winner. The gloves come off this week with evidence that high-carb diets could be more effective by a substantial margin.
But Low-Carb Diets Have to Yield More Fat Loss, Right?
I’m a fan of supervised nutrition studies. Experts conclude that self-reported studies average 30 percent inaccurate or under-reporting. Consider an inpatient study that provided subjects with both a month of high-carbohydrate dieting and a ketogenic diet of the same caloric intake. They measured energy expenditure in metabolic chambers to see if lower-carb intake would result in increased body fat loss due to less insulin production and thus conversion of carbs to fat. Makes sense, right? The opposite happened. The high-carb diet resulted in more body fat lost.
Which Diet is better for Metabolism?
Some post weight-loss metabolic adaption and suppression is normal. Energy expenditure was measured in subjects who had achieved 10 to 15 percent weight loss using diets based on:
60 percent carbs, 20 percent fat, and 20 percent protein in one group
40 percent carb, 40 percent fat, and 20 percent protein in another group
10 percent carb, 60 percent fat, and 30 percent protein in the last group.
After four weeks, the greatest resting energy expenditure was found in the lowest-fat group with the highest carbs. The slowest metabolism was recorded in the low-carb/high-fat group. That is quite an indictment against low-carb dieting for the purpose of weight loss. A higher-carb diet sustains metabolism better than a low-carb diet.
How Does a High-Carb Diet Yield More Fat Loss?
Context is king. Too much carbohydrate is still too much, right? Eh…kind of. Therein lies the reason for high-carb superiority. Converting carbs to fat isn’t as easy as commonly described. One very large meal of 500 grams of carbs is shown to contribute very little to fat gain, though obviously it will slow fat loss. The physiology of carbohydrate digestion accounts for glycogen storage, but oxidation increases with carb ingestion—faster metabolism of those carbs. Much less fat is stored due to carb consumption than most claim. Once again I quote the physiology gods: fat burns in the flames of carbohydrates.
Self-reporting studies might show mixed results, but supervised studies conclude that a lower-fat diet is conclusivel better for weight loss, weight maintenance, and even at preventing diabetes and elevating immunity.
Knockout in the Fifteenth Round—Carbs Win!
If one large meal doesn’t convert substantially to fat, what about more carbs over time as glycogen stores saturate? Another study increased subjects’ carbs by 250 grams per day for 21 days (a total of 5,250 increased grams), only to report a conversion of 332 total grams to fat—6 percent. Only when massive carb loading is utilized for a consistent length of time does fat storage increase from carbs.
One supporting nuance of interest is fructose. A popular myth states fructose is converted directly to fat since muscle cells can’t metabolize it. In a study using between 50 and 150 grams of fructose on a daily basis, less than 1 percent was converted to lipids. There you go—sciencing isn’t so difficult after all.
A Calorie Isn’t Just a Calorie
Biological math may not be linear, but it’s not all fairy dust and unicorns either. Remember context. For example, a ketogenic diet can reduce the risk of heart disease and cancer substantially, but it loses all benefits if the dietary fat ingested is from saturated sources. Similarly, if a high-carb diet is to be maintained, it must be remembered that excess fat consumed along with a higher-carb diet will have a greater likelihood of increasing fat stores, reducing fat loss, and increasing risk of health malady…not because of the carbs, but because of the fat. A higher-carb diet is followed with the best efficiency if a person adheres to a low percentage of fat—especially saturated fat.
Low-Carb Diets Fail in the Real World
How about a little illustration to wrap up this series? Anecdotal narrative is the force that drives science. It opens doors and guides research. I’ll share a couple recent client stories. One gentleman presented with a diet that included 150 grams of fat and only 30 grams of carbs. He was smitten with the Paleo lifestyle. With his partnership, I suggested a gradual reversal of those caloric sources so at the end of four months, we ended up at half the amount of fat and we reached 250 grams of carbs. He lost 20 pounds of body fat, increased lean body mass by a couple of pounds, and reported feeling stronger and more energetic. A female client recently presented with the same low-carb influences. In one week of reducing fat by 15 to 20 percent while doubling carbs, her weight trended down and she reported more energy and deeper sleep. More energy, more strength, more lean body mass, faster fat loss, and better rest—welcome back, carbs.