Is “cutting on carbs” necessary during body fat reduction? Part I

Two decades ago almost everybody believed that “you put on weight because of fat intake”. Nowadays, the belief that carbohydrates are guilty of the problem of overweight and obesity is getting more popular. Therefore, decreasing its consumption is associated with working on shape during fat reduction period. However, is this belief right? Following the available literature, one can really hesitate about that.

Slimming on the low-carb diet

There's no doubt that introducing carbohydrate restrictions may be an efficient way of losing excessive amount of fat from the body. There are some controversies around the safety of using the low-carb diets, however, there are more studies indicating that such solutions are safe for health – if they are well-planned. So, against common worries, neither decrease of carbohydrate intake, nor the increase of the supply of fat is threatening for health. There is even evidence that in the group of obese people, the low-carb diet may lead to the improvement of some health parameters (e.g. there were positive changes in lipidogram, the level of insulin and glucose on empty stomach, the level of the indicators of inflammation processes, such as some interleukins, or TNF-alpha).

Too far-reaching conclusions

Quite high efficiency of low-carb diets in the process of body fat reduction noticed in research has caused many people to draw conclusion, that decreasing the carbohydrate supply is necessary to cause the reduction of excessive body mass. What's interesting, the authors of the studies, in which the low-carb diets were very advantagous, don't really confirm that news, however, people who write blogs, books or articles about nutrition and the problem of overweight and obesity, often copy that information. It's good to think whether such statement is correct and if losing weight should be really based only on “counting carbs” not on “counting calories”.

The flaws of studies with the use of low-carb diets

The problem with articles, or discussions, in which the followers of low-carb diets support their theses with the results of research is that such studies are usually designed in a biased way. It often happens that, when the authors of such studies give the volunteers to the low-carb or high-carb diet, there is usually more protein in the first group (but this fact is omitted in discussions). You just need to look at the publications linked below to be convinced about that:

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC538279/

http://www.ncbi.nlm.nih.gov/pubmed/18046594

http://www.ncbi.nlm.nih.gov/pubmed/19082851

If we looked at it from other perspective...

The fact mentioned above may influence the results of the cited studies. After all, it's been known for a while now that higher intake of proteins may cause additional advantages during body fat reduction process (I mean, decrease of hunger, blocking catabolism and speeding up the tempo of metabolism). Of course, it doesn't have to belittle the positive influence of carbohydrate restrictions on the process of slimming, however, it is an additional factor worth taking under consideration, and the authors – as it turns out – don't always remember about that. Does it mean that there are no comparative studies in case of the same level of protein intake? Of course, there are, but the differences between low-carb and low-fat diets are not that significant. The experiment, in which there was the comparison of efficiency of the following nutrition solutions turned out to be very interesting:

  • diet with normal content of carbohydrates and moderate content of protein (NPNC),

  • diet with low content of carbohydrates andmoderate content of protein (NPLC),

  • high-protein diet with normal content of carbohydrates (HPNC),

  • high-protein diet with low content of carbohydrates (HPLC).

The experiment was designed to assess the real influence of the changes in the protein intake on the final result.

What did it turn out?

The authors observed that the diets richer in protein were more advantagous in the matter of body fat reduction than the diets with lower content of this component. The result was independent from fat or carbohydrate intake (the calorific content of diets was the same). The results of this study show a bit different perspective of the results of the experiments which compared the effects of low-carb diets with conventional diets, but without noticing that the level of proteins was different in both diets. For more interested ones, here is the link to the study:

http://www.ncbi.nlm.nih.gov/pubmed/22935440

Of course, the fact described above does not disqualify the low-carb diets as a method of lowering the excessive body mass, however, it shows that the results of many studies may include some error. Even Lyle McDonald paid attention to that fact long time ago (do not mix up his surname with the famous fast-food chain) – he's a specialist who prepares and describes the protocols including carbohydrate restrictions. But, he doesn't approach the nutrition matter in the dogmatic way, nor does he add the meaning of “the calorific balance” in the process of planning the reduction diets. The energy balance is the key factor and it is implacable if it comes to the influence of diet on the loss of excessive centimetres and kilograms, what was shown on the example of an American teacher, who managed to lose weight when eating only products from fast-food restaurant only.

Summary

I think, that the information written here – although it does not cover the topic of “necessity” of lowering the intake of carbohydrates during the body fat reduction period, it will throw another light on this matter, than that, which is currently present in the carbohydrate restrictions from the youtube channels, various portals, Internet forums and blogs. I will also add, that it's not over of the deliberation on this topic. In the next part of this article I will refer to quite interesting research, in case of which there was the comparison of low-carb and low-fat diet in very rigorous and objective conditions.

Is “cutting on carbs” necessary during body fat reduction? Part II