A new clinical study was just released linking a low-carbohydrate diet to reduced liver fat. Get this, though – the scientists actually compared the low-carb diet to a low-calorie diet and found the low-cal diet severely lacking. Their results aren’t surprising, especially to our readers. In fact, we’re almost tempted to put this in the “Duh” files, but these guys seem to be on our side: they went into it with a hypothesis that maybe, just maybe, a low-carb diet could be helpful, and the results speak for themselves. A study that’s actually intended to investigate the advantages of a low-carb diet without the underlying assumption that CW-driven low-cal diets are better? No way we’re passing up a chance to discuss it!
Still, even the language used in the press release seems a bit misleading: “people on low-carbohydrate diets are more dependent on the oxidation of fat in the liver for energy than those on a low-calorie diet.” It almost sounds like a negative, doesn’t it? But that’s probably just us being hypersensitive. After years and years of CW and low-cal and low-fat diet talk, you can’t blame us for jumping the gun.
That said, it warms our hearts to hear a lead researcher for once say, “Instead of looking at drugs to combat obesity and the diseases that stem from it, maybe optimizing diet can not only manage and treat these diseases, but also prevent them.” This was admittedly a rather “small clinical study,” but the very fact that this type of research is receiving funding is fantastic. The team from UT Southwestern Medical Center, led by Drs. Jeffrey Browning and Shawn Burgess, was examining the effects of diet on glucose production and utilization in the liver. As we already know, both glucose and fat are metabolized in the liver and converted into energy for our bodies. Glucose can come from lactate, amino acids, or from glycogen (ingested carbohydrates and sugars). Browning and Burgess randomly assigned fourteen overweight or obese adults to either a low-carb or a low-calorie diet. After two weeks, they analyzed the biochemical pathways each group used to make glucose.
The low-carb group got most of their glucose from lactate or amino acids; the low-calorie dieters got about 40% of their glucose from ingested carbohydrates. But the truly interesting discovery was that because the low-carbers didn’t have much glycogen to burn, their livers started burning fat for energy instead, especially liver fat. Indeed, “results indicate that patients on the low-carbohydrate diet increased fat burning throughout the entire body.” (This can probably be explained by the formerly fatty liver being freed up to do a better job of removing excess insulin; a fatty liver can’t process insulin effectively, so reducing your carb intake burns fat in the liver which in turn allows it to process more insulin, effectively lowering your insulin levels and promoting less storage of fat… whew!)
Losing fat, as we already know, isn’t just an aesthetic advantage, but a boon to our overall health (take that, “fat but fit” crowd), a strangely foreign idea to way too many in this country. Not to Browning and Burgess, thankfully, who suspect a low-carb diet might pay huge dividends for people with nonalcoholic fatty liver disease (NAFLD), which is caused by (surprise, surprise) excess liver fat. In fact, Browning and Burgess’ next study will examine the effects of low-carb diets on liver metabolism in people with NAFLD (we don’t like giving spoilers, but we think we know what their results might be).