Low-Carb versus High-Carb Diet

Some of you may know that I have been pursuing a very low carb diet for several years now. I don't share this too often, because the common wisdom is that low fat is healthy and high fat is not. I often get people proving to me that my diet is unhealthy, because in Japan and the Mediterranean they have a longer life span and the traditional Japanese diet is extremely high carb and low fat and of course Japan is considered one of the healthiest countries in the world. How can this be. I've decided to try and answer this question with some data to help explain what I think is happening.

Since I spend a lot of time in Japan, this is a question that plagues me and I will present here a combination of personal theories based on the work of ex-New York Times Science writer Gary Taubes in his two books Good Calories, Bad Calories and Why We Get Fat. Taubes, by the way is not some self-promoting diet Guru, but someone who spends a lot of time researching the actual studies that many fanciful theories have been based upon and debunking them.

I was asked recently whether all human bodies are basically the same (in terms of diet help) or whether there are body types that mean we are different and thus need to rely on different diets for staying and getting healthy.

Here is my response: In Why We Get Fat (pages 168-170 ) Taubes suggests that human bodies are all basically the same. Data show that people that migrate from one country to another take on the health issues associated with the diet of the country they move to. (For example, Japanese women have less breast cancer and alzheimers disease than when they emigrate to the US and begin to eat an American diet. African Americans have greater instances of heart disease etc. than people eating their native diets in Africa.)

So, if high carb diets are so unhealthy, then why didn't the Japanese have more health problems before they started adding in Western foods? One has to read between the lines to try and puzzle out an answer, but here is what I can say based on Taubes.

1. Taubes notes that the diet eaten by Sumo wrestlers to bulk up basically doubles the amount of carbohydrates in the typical Japanese diet. Top-tier wrestlers ate about 5500 calories (780 grams of carb, 100 grams of fat and 365 grams of protein) in their Chanko nabe (pork/vegetable stew with added rice (see image below)). The fatter, but less muscular second tier of Sumo wrestlers consumed 5120 calories, but ate 1000 grams of carbs, 50 grams of fat and 165 grams of protein. (Note that the heavier group ate fewer calories, so calories in/calories out is not the whole story!) The average Japanese diet according to The Japanese Ministry of Health and Welfare (1972) was 359 grams of carbs, 50.1 grams of fat and 82.9 grams of protein. (pages 306-7 Good Calories, bad Calories). Taubes uses these data to show that increasing carbs can lead to pathological obesity. (One might add here that the average life span of a Sumo wrestler is 60-65 years more than 10 years less than the average Japanese citizen.)


2. Taubes also notes that in the 1870s when the Japanese switched over to eating (polished) white rice rather than brown - they had outbreaks of beriberi in the Japanese navy. This was cured by replacing the white rice with barley (less refined food) and adding into the diet meat and evaporated milk. (page 321 GCBC). Thus even though we think of the Japanese as eating lots of rice. This is a relatively new development and most Japanese carbs were originally unrefined and found in vegetables. Even now, rice is eaten at the end of the meal as a kind of dessert (for the most part) and not in huge quantities.


3. Taubes points out on page 211 of GCBC that the Japanese eat considerably less sugar than other nations (traditionally) (Along with Yugoslavia, Spain, Portugal and Italy).


4. We see that the carb ingestion in Japan is relatively high (359 grams compared to 50 fat and roughly 83 grams of protein (roughly 73%)). Taubes' best explanation for their health despite a high carb diet is found on page 177 of GCBC. He suggests that after WWII some populations (Japan, Greece and other Mediterranean cultures) barely eked out an existence after the war and that their diets were characterized by a "near absence of refined carbohydrates" little heart disease and "a relative lack of of calories" and that this diet was not eaten by choice, but by necessity. To me this suggests that if you are using up (physically) the food value you ingest that you have less to worry about; that it is only when you eat a surplus of calories/food that issues of carbs versus fats and proteins become truly significant and that unrefined carbs (for whatever reason) are less damaging than refined ones.

My two cents: I know that Taubes believes exercise and calories are relatively unimportant for weight loss, but it seems to me that one must take into account the destructive effects of some diets on the body. For healthy individuals who eat only what their bodies need food-wise and get exercise, their metabolisms seem to run smoothly and also cause them to properly dispose of these "fuels" without increasing fat. I suspect that if we eat excess carbs together with excess calories, the body decides to store away the carbs for later and that this alters or damages the system. (If we eat excess calories with few carbs there seems to be evidence that we are less likely to store those substances as fat.) This is all theoretical and needs some research and relates I believe to healthy people who are not overweight. It seems like once the fat storage system begins to work overtime, then carb processing becomes problematic and I believe that is when we start to see all the diseases developing.

So do we believe that there are different body types and things that work for some as opposed to others? Well, if the above is correct, then it would seem there are and there are not. We might all start off pretty much the same, but depending on what we have subjected our bodies to and how fat we have gotten, then that might alter our needs and "best practices".

Do I personally believe that there is a genetic component? Yes. Some of us have genetic defects and I am assuming that this is possibly the case before we unintentionally alter our needs via poor diets or lack of exercise. How significant a role do these genetic components play in differences in dietary needs? It is hard to tell. It might be that those genetic predispositions would be minor or insignificant if we all ate the low carb diet that seems to be most healthy for humans.

Bottom line ( My Opinion) Refined carbs and sugars aren't good for anyone and eventually break our systems. Healthy people who eat non-refined carbs, have regular exercise and eat at the boundary of what their caloric/fuel needs in terms of food can probably eat high carb without significant health problems. Storing excess fat disturbs our mechanisms such that we cannot eat a higher carb diet without significant health repercussions. A complicated theoretical answer to a seemingly simple question.

(I highly recommend the books by Gary Taubes, Good Calories, Bad Calories and Why We Get Fat. For more info there is also Wolfgang Lutz' book Life Without Bread.