The million dollar question in the nutrition community these days: Does the amount of total fat in your diet make any difference in terms of heart health, diabetes, obesity, etc, or should we be just worried about the kind of fat? Controversy over whether reducing saturated fat matters to your heart and is the best prescription for health is the basis of an ongoing debate. Some experts maintain that traditional low-fat guidance still has some value, and others challenge the importance of total fat intake.
Saturated Fats
Saturated fats are found in animal products such as butter, cheese, whole milk, ice cream, cream, and fatty meats. They are also found in some vegetable oils like coconut, palm, and palm kernel oils. Saturated fats are the biggest cause of an increase in low density lipoproteins (LDLs, or "bad cholesterol"). LDL levels that are above120 mg can significantly increase your risk of heart disease. Some experts believe limiting intake of saturated fatty acids to less than 10% of calories will fall into place if people eat more healthy fats, less red meat, and more plant protein.
Unsaturated Fats Unsaturated fats are found in most (but not all) liquid vegetable oils and have been shown to help lower total blood cholesterol if used in place of saturated fats. However, unsaturated fats have a lot of calories, so using these in moderation is key. There are two types of unsaturated fats:
Monounsaturated fats are liquid at room temperature but begin to solidify at cold temperatures. This type of fat is preferable to other types of fat and can be found in olives, olive oil, nuts, peanut oil, canola oil and avocados. Some studies have shown that these kinds of fats can actually lower LDLs and maintain high density lipoproteins (HDLs, or "good cholesterol"). HDL levels above 60 mg have been shown to significantly protect your heart from heart disease.
Polyunsaturated fats are also liquid at room temperature. These are found in safflower, sesame, corn, cottonseed and soybean oils. This type of fat has also been shown to reduce levels of LDLs, but too much can also lower your HDLs.
Trans fats are actually saturated fats and form when vegetable oil hardens (a process called hydrogenation). They are used to extend the shelf life of processed foods, typically cookies, cakes, fries and donuts. Any item that contains “hydrogenated oil” or “partially hydrogenated oil” likely contains trans fats. Trans fats are dangerous because they decrease HDLs and increase LDLs.
So now that we've met all the players in the game, lets take a look at the different sides of the debate:
Side #1: Total fat doesn’t matter in regards to heart disease, diabetes, cancer, or weight gain, but saturated fat could be the culprit! Increase those polyunsaturated fats to reduce heart disease risk. A diet that is high in total fat may have a slight advantage for weight loss. Recent data suggests no relationship between total fat and heart disease, therefore the focus on reducing the total fat in the diet is not as relevant as focusing on the type of fat in the diet. This side goes as far as to say the percent of calories from fat should be removed from the dietary guidelines and total fat should be removed from food labels. The take home message from this side of the debate: stop focusing so much on total fat in your diet, its not that important.
Side #2: Total fat doesn’t matter in regards to heart disease, diabetes, cancer or weight gain, but neither does saturated fat, focus on those carbs!
As stated in the side #1, many studies show total fat in the diet is not related to heart disease, but evidence also shows the same conclusions for saturated fats. Dietary quality is very important, and we should focus on increasing the quality of carbohydrates (i.e. increasing consumption of whole grains and decreasing consumption of refined carbohydrates) and increasing the amount of polyunsaturated fats in our diets. Quite often reducing fat in the diet causes an unintended increase in refined carbohydrates. The take home message from this side of the debate: the average carbohydrate in the U.S. diet is worse than saturated fat.
Side #3: Total fat doesn't matter, the overall dietary pattern matters the most.
This side focuses on dietary guidelines and how they have changed over the years. Historical data suggests increasing both polyunsaturated and monounsaturated fats in place of saturated fat can lower heart disease risk, but replacing saturated fat with carbohydrates isn’t really supported in that data. The take home message from this side of the debate: focus on what foods are replacing the fat when a person is on a low-fat diet. Side #4: Saturated fats increase total cholesterol and the risk of heart disease.
We shouldn't be fixated on the amount of total fat in our diet, but instead watch those saturated fats we put in our mouths. This side is obsessed with LDL levels, and stresses that we need to get that number under 100mg to decrease risk of heart disease. Also emphasized by this side is the fact that eating behavior is a big problem in the United States, as a whopping 48% of our food is consumed outside of the home. The take home message from this side of the debate: check those LDL levels religiously and keep dinners at home.
Wow, that's a lot of information! But who is correct, and what should we really do? I think there are a couple of overall themes that all sides seem to agree on:
1. The amount of total fat in the diet isn't the issue
...and...
2. Increase those polyunsaturated fats in the diet
Lean Steak Salad
4 oz lean steak, cut into strips
4 cups spinach1 cup arugula
4 to 5 slices red onion
4 to 5 slices red pepper
2 basil leaves, cut into strips
10 cilantro leaves
1/4 cup lime juice
1/2 cup reduced sodium soy sauce
1/2 cup canola oil
1/4 cup light brown sugar
1 tbsp diced garlic
1 tbsp chili garlic sauce
- Cook steak.
- Toss first 7 ingredients together
- Combine lime juice, soy sauce, canola oil, brown sugar, diced garlic, and garlic chili sauce and whisk until mixed.
- Top spinach mixture with dressing. Toss to coat.
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