The Problem with Low-Fat Foods and Low-Fat Diets
January 29, 2015
The Problem with Low-Fat Foods
- Often lower in calories, but people assume they can eat more.
- Studies have shown up to 245 calories more are eaten if it was known that food was “low fat” (this is more than the amount of calories burned in a 45 min bout of aerobic exercise).
- Belief about calorie content also affects the way you feel after eating. You will feel hungrier more quickly after a low fat meal because you know that it’s low in fat.
- Or, we think we can get away with more food after eating a low fat meal.
- Low fat foods can help promote weight loss, however it is important to guard against the tendency to eat more food later on. Low fat does not mean all you can eat.
- Also, there are often more trans fats in low fat foods.
- Low levels of trans fat in meat and dairy are formed when oil or fat is transformed into a semi-solid or solid state through hydrogenation.
- USDA hydrogenated oil = solid at room temp.
- Partially hydrogenated oils = liquid at room temp. Partially hydrogenated oils are usually higher in trans fats.
- The idea behind hydrogenation was to transform oils into products used for spreading (i.e., to replace butter). Hydrogenation occurs by heating oil to extremely high temperatures, mixing it with nickel powder, and forcing hydrogen through it. Foods appear creamier, spread more easily, and have a longer shelf life than most oil.
- Fats used by many restaurants for deep frying are also hydrogenated and less likely to become rancid.
- Hydrogenated oils are used instead of saturated fat because they are almost as stable and people are concerned about saturated fat.
- They interfere with the metabolism of essential fatty acids. AJCL reports trans fats can destroy natural essential fats, inhibiting the desaturation of linoleic and linolenic acid.
- Trans fats raise lipoprotein (linked with CHD) seen in people with relatively high lipoprotein levels to begin with.
- Some say concern about trans fats is exaggerated because they make up only a small portion of our fat intake. However, it is difficult to tell from food labels exactly how many trans fats you are consuming. If you see partially hydrogenated oil on the label, you know the food contains some trans fat, but don’t know how much. Anyone concerned about health might choose a product low in saturated fat and cholesterol without realizing that it’s also high in trans fats. Public perception remains that saturated fats are bad so manufacturers will continue to use hydrogenated oils, and they remain “invisible” on labels.
- Some estimate trans fat consumption at 8-13 grams daily, while others put this figure much higher.
- Many ready-made, low-fat meals, i.e., Weight Watchers, contain hydrogenated or partially hydrogenated oils.
- Rather than choosing what to eat based on what a food doesn’t contain, i.e., fat, base choices on what it does contain. Choosing foods high in nutrients, i.e. fiber, protein, essential fatty acids, vitamins and minerals, is always a better choice.
Problems with Low-Fat Diets
- Tend to restrict choices of foods – foods commonly included are meal replacement bars, ready-made meals, and low-fat desserts. These all contain ingredients which can potentially slow fat loss.
- Certain types of low-fat foods can trigger hormonal changes that stimulate your appetite, promoting excessive food intake in overweight people. Studies show a low-calorie diet deriving 35% of the total calories from fat will help you keep weight off longer.