Most of the people I talk to about nutrition are convinced that carbohydrates are their enemy. They think that “sugar spikes” cause diabetes. (They have it backwards. Sugar spikes are the result, not the cause of diabetes!) People seem to be particularly worried about the effects of a sugar called fructose. Personally, I’m not worried about carbohydrates, even fructose, as long as it’s found in an unrefined plant source. I even think that adding a spoonful of sugar or perhaps some maple syrup every now and then could help a lot of people stick to a healthy low-fat, plant-based diet.
Genetically, human beings are almost identical to chimpanzees. Our DNA is almost exactly the same as theirs, which means that our body chemistry is also almost exactly the same as theirs. Since chimpanzees, like many other apes, are mainly fruit-eaters (frugivores), it stands to reason that they probably thrive on a diet that contains a lot of fructose, which is a sugar that is common in fruit. However, the fructose that wild chimpanzees eat is diluted with water and fiber and packaged along with plenty of other nutrients, along with antioxidants and other good things.
Yes, you can make yourself sick by eating too much sugar. However, it would be difficult for most people to get that much sugar from eating fruit! One study found that eating way too much added sugar (at least 25% of total calories!) is associated with only a relatively small increase in the amount of fat (triglycerides) in the blood and a small decrease in the level of HDL (“good”) cholesterol. Of course, if you are having a problem with triglycerides, you should probably cut way back on your consumption of table sugar and high-fructose corn syrup.
Sugar does rot your teeth, at least if you don’t brush carefully after meals. As a result, chimpanzees are prone to dental caries (cavities), just as humans are. However, wild chimpanzees don’t seem to be fat and diabetic and they don’t get heart disease. So why should I imagine that I would get fat and diabetic and suffer from heart disease if I ate a lot of fruit?
Eating lots of sugar does not cause diabetes. Instead, cow’s milk seems to be the culprit in causing type 1 diabetes. A diet that is high in fats and animal protein seems to be the underlying cause in type 2 diabetes.
Eating too many calories from any kind of diet tends to make people gain weight. However, you gain a lot more weight from extra calories from a fatty diet than from extra calories from a high-carbohydrate, low-fat diet. Converting sugar to fat wastes calories. That’s why it’s hard to fatten on carbs but easy to fatten on fats.
Of course, there are a few people with genetic disorders that make it hard for them to tolerate fructose. One of them is hereditary fructose intolerance. Another is fructose malabsorption.
Hereditary fructose intolerance is a potentially fatal genetic disorder that occurs in about 1 out of 20,000 people in European countries. The disorder results from the lack of an enzyme called aldolase B. In people with this disorder, eating anything containing fructose, including sucrose (table sugar), sets off a series of complicated metabolic problems that can ultimately cause liver damage. The only solution is for these people to avoid any foods that contain sucrose or fructose.
Fructose malabsorption is an unrelated problem that is far more common but much less serious than hereditary fructose intolerance. Fructose malabsorption results from the absence of fructose transporters in the cells that line the small intestine. Without fructose transporters, the person cannot absorb fructose from his or her food. Even people who have some fructose transporters might be able to absorb only a limited amount of fructose. The remaining fructose will then remain inside the intestines, where it will be fermented by bacteria. The result is syndrome that looks a lot like lactose intolerance: gas and diarrhea. Fructose malabsorption is a common but often undetected cause of recurrent abdominal pain in children.
Fortunately, I don’t have hereditary fructose intolerance or fructose malabsorption. This means that I can eat as much fruit as I like!
Note: For a clear explanation of how the body handles sugar, see my book Thin Diabetes, Fat Diabetes: Prevent Type 1, Cure Type 2.
You wrote that it’s “easy to fatten on fats.” I won’t dispute that, but from a practical standpoint, no one really eats fat by itself. Butter by itself is pretty gross! haha. It’s various combinations of fat, carbs, and protein that cause people problems. The carb/ fat combination seems to be particularly palatable (ice cream, chocolate, pastries, etc.) It seems like it’s the palatability of foods that leads to overeating, which leads to weight gain. Maybe that’s one of the reasons why people can lose weight on low carb diets, because it reduces that addictive carb/ fat combination. A low fat diet would do that, too, of course.
It doesn’t really matter whether the fat is “by itself” or fried into a donut, does it?
Yes, it matters a great deal. Because butter, vegetable oil, shortening, etc., are not palatable by themselves, but a donut is extremely palatable! That donut isn’t just fat, it’s fat + sugar + refined flour. I’m just saying that, in real world conditions, we’re far more likely to overeat that fat when it’s made palatable via various combinations of refined sugar, refined flour, salt, and, of course, fat.
So, in terms of “fattening up” on fat, it only happens in the presence of those other substances, so they are contributors, as well. Very few people would eat much butter, vegetable oil, or shortening if they had to eat them separately. I wouldn’t eat any! Zero. Zilch. Nada. 🙂
I’m speaking from personal experience because this is something I’m struggling with right now. I’m trying to reduce my intake of highly palatable foods (fat + sugar + flour + salt) and needless to say, it’s extremely difficult.
Are you really “overeating” or simply eating the wrong food? To get enough calories from eating leafy vegetables, you’d have to eat 12 pounds of food per day. To get enough calories from just potatoes, you’d have to eat 20 medium potatoes a day. That’s a vast volume of food when compared to the amount of donuts that it would take to make you fat. If you simply cut out the fatty foods altogether and ate a lot more fiber, your weight would almost certainly regulate itself. You could even eat some sugar.
That’s a good point. It’s probably a bit of both. Overeating the wrong food! That’s the key. I guess, theoretically, one could eat one donut per day, which wouldn’t cause weight gain. Much easier said than done though. The problem with these foods is not just the calorie density, but the lack of portion control. Maybe it’s because they affect brain chemistry or whatever, but it’s really hard to eat these foods in moderation. It’s not one donut that’s the problem, it’s two or three or four donuts!
I have nothing against reducing fat, of course, otherwise I wouldn’t be reading your blog. 🙂 But if someone decided to cut out all refined sugar and white flour, they could do pretty well, too, don’t you think?
For example, lot of people drink too much soda, which is pure sugar. Some people drink several cans of soda per day. Fortunately, that’s not my problem, I haven’t drank soda regularly since I was 12 or 13. I’m all about the fat/ sugar combo! haha. But it’s a big problem for lots of people.
Here’s an interesting analysis of calorie intake:
http://fathead-movie.com/images/CalorieBreakdown.jpg
Get rid of added sugars, fats, and oils, and a 2600 calorie American diet becomes a 1600 calorie diet! (Barring substitutions, of course.) Sugar + fat + flour = lots of calories.
Wow. Also, don’t forget that a lot of the calories from the meat, poultry, fish, and eggs and dairy foods also come from fat!
I was a little surprised by the calories from fats and oils. I know people eat a lot of fried foods, and use butter and oils for cooking, but over 600 calories per day is a lot.
And only 90 calories per day from fruit! That’s sad. 90 calories is a medium size apple, and nothing else. I’ve actually heard people say that they don’t like fruit. Weird. What’s not to like? It’s like the aggressive flavoring of processed foods has distorted our perception of what tastes good.
Maybe they’ve never eaten really fresh fruit?