Tag Archives: low fat diet

Fat still matters

Last week I wrote about some recent research suggesting that low-carbohydrate diets may be better for weight loss that low-fat diets. For many, this study reinforced the notion that traditional recommendations are wrong and that the key to good health is to eliminate carbohydrates from your diet. This couldn’t be further from the truth.

The recent study did show that people lost more weight and experienced beneficial changes in blood lipids when they followed a low-carbohydrate diet compared to those who ate a low-fat diet. However, this does not mean that low-fat diets aren’t effective for weight loss or that they are “unhealthy.”

In fact, low-fat diets have long been used effectively to promote weight loss, reduce heart disease risk, and lead to healthier eating in general. This is supported by the results of hundreds of research studies as well as the practical experience of health professionals and real people. Here are two reasons why fat still matters when it comes to health.

First, reduced-fat diets have been shown to improve blood cholesterol and lower the risk for heart disease. Eating a diet low in fat, especially saturated and trans fat, has been the foundation of nutrition recommendations for decades. The fact is that these diets are effective for weight loss, reducing cholesterol, and otherwise improving heart health.

One famous study demonstrated that following a low-fat diet contributed to a reduction in the severity of atherosclerosis, the narrowing of arteries that leads to many heart attacks. Literally hundreds of other studies have shown similar beneficial results.

This isn’t some magical effect of eating less fat, though. The health benefits are likely due to eating more vegetables, fruits, and whole grains as much as they are to reducing fat intake. The point is that adopting a low-fat diet can lead to better nutrition overall.

Second, reducing fat intake is a good way to reduce calories. This is true because fat contains nine calories per gram, more than twice that of carbohydrates and protein, so cutting fat is an effective way to cut calories. Limiting fat intake also reduces calories indirectly because many high fat foods are also high in sugar and calories (think of most desserts).

It is important to mention that simply reducing fat intake won’t always lead to weight loss; total calories must be lower, too. This is a mistake many make when they reduce fat intake, but increase the amount of calories from other sources, typically carbohydrates. Many low-fat foods are actually relatively high in calories due to added sugar or people tend to eat more of them (the SnackWell Effect).

The effectiveness of low-fat diets for weight loss has been demonstrated in research studies (like this one) and countless weight loss programs. In one notable study, a diet low in fat even led to weight loss in people who weren’t trying to lose weight. And don’t forget that in the recent study about low-carbohydrate diets, the subjects that followed the low-fat diet also lost weight.

For some people, cutting carbohydrates as a way to lose weight is reasonable; for others, reducing fat intake makes sense. For most people, though, doing both to some extent is the best option, but going to extremes is unnecessary.

Eating less added sugar and avoiding foods with added fats (such as French fries) are good recommendations for almost everyone. That said, there is little evidence for the benefit of limiting carbohydrates in the form of whole grains, legumes, vegetables, and fruits or the fat in meat and dairy.

The bottom line is that the quality of food we eat is more important than the specific amounts of the nutrients it contains. Eating low-carbohydrate or low-fat diets can help steer you toward making healthier choices, but so can avoiding processed foods in favor of wholesome, nutrient-dense “real” food.

The diet wars continue

If you are confused or frustrated by the conflicting claims about whether a low-fat or low-carbohydrate diet is the best, you are forgiven. First we were told that eating a low-fat diet was the best way to lose weight and improve heart health. Then, research suggested that low-carbohydrate diets were better. And back and forth it has gone for years.

During this time, the prevailing recommendations have suggested that a diet low in fat and high in carbohydrates was best. But more and more research has supported the notion that cutting carbohydrates, not fat, would lead to greater weight loss. Although this has been supported by some research, critics pointed out that eating more fat would raise blood cholesterol and other risks for heart disease.

According to a recent study, though, low-carbohydrate diets seem to have benefits for promoting weight loss and improving some indicators of heart health over low-fat diets. But you should hold off on shunning fruits and vegetables in favor of cheeseburgers! Here is a practical interpretation of the research and some common sense recommendations, taken from my Health & Fitness column in the Aiken Standard this week.

The study, published last week in the Annals of Internal Medicine, reported on 150 men and women who either restricted the amount of carbohydrates or fat they ate. After one year, the group that ate a low carbohydrate diet lost over 7 pounds more than the subjects on the low-fat diet. Additionally, the low-carbohydrate diet promoted greater improvements in blood lipids than the low-fat diet.

This is important for two reasons. First, this wasn’t a weight loss study; the researchers were simply following the subjects to see what would happen as they followed either diet. The fact that the low-carbohydrate group lost more weight suggests that it is relatively easier to cut calories following this type of diet.

This is consistent with other research showing that eating more carbohydrates, especially refined carbohydrates and sugar, can actually make people feel hungrier and eat more. Indeed, other studies have shown low-carbohydrate diets to be more effective for weight loss than low-fat diets (although a more recent study suggests there isn’t such a difference).

Second, the greater decrease in triglycerides and “bad” LDL cholesterol and increase in “good” HDL cholesterol in the low-carbohydrate group were different from what might be expected. Conventional wisdom holds that a low-fat diet should have a greater effect on blood lipids. Since weight loss can have a big effect on blood lipids, the improvement in the low-carbohydrate group may be due to losing more weight, not a direct effect of the diet.

It is important to note that the low-fat diet also led to weight loss in this and numerous other studies. The critical component of any weight loss diet is that it is relatively low in calories, regardless of what nutrients supply those calories. Really, almost any diet will lead to weight loss as long as it contains less energy than what is expended, but a low-carbohydrate diet may be more effective for weight loss than the traditional low-fat diet.

The bottom line is that the best diet is one that emphasizes eating wholesome foods, not on cutting carbohydrates or fat. That said, limiting carbohydrates in the form of refined grains and added sugar is an excellent way to reduce calorie intake and improve the overall nutritional value of what you eat. And shifting toward more monounsaturated fats (think olive oil and nuts) rather than worrying about the total amount of fat you eat is also a good idea.