Within the vast and sometimes contradictory world of nutrition, two dietary contenders often battle for the weight-loss limelight: low-fat and low-carb diets. Although these regimens vary greatly in their approach and principles, they seek a shared goal of weight management---while professing additional health perks as well. Both diets offer potential benefits and drawbacks that dieters should consider before embarking on either eating plan.
Description
According to EveryDiet.org, low-fat diets limit daily fat intake to 20 percent to 30 percent of total calories consumed; very low-fat diets limit fat to 0 percent to 19 percent of total calories. This necessitates curbing the consumption of high-fat products such as eggs, meat, full-fat dairy, cooking oils and nuts, while emphasizing high-carbohydrate food sources.
Conversely, low-carb diets limit the consumption of dietary carbohydrates, which are abundant in foods like grains, fruit, starchy vegetables, bread, sweets and desserts. In place of carbohydrates, protein and fat serve as the the primary energy sources on low-carb diets. The level of allowable carbohydrates differs between low-carb eating plans such as the Zone diet, Protein Power, the Atkins diet and the South Beach diet; some regimens mandate a stricter avoidance of carbohydrates than others.
Effects
Because fat is the most caloric macronutrient---providing nine calories per gram opposed to four in protein and carbohydrates---low-fat diets facilitate weight loss by reducing total calorie intake. The high fiber content of low-fat foods like vegetables also encourages a lower calorie intake by creating long-lasting satiation.
Initially, low-carb diets force the body to burn water-rich glycogen for energy, resulting in a rapid loss of water weight. Although this causes the numbers on the scale to drop, the weight loss doesn't represent a reduction in fat---just hydration. Because low-carb diets strictly limit your menu options, nixing mealtime staples like grains and starchy vegetables, they reduce your total calorie intake and induce weight loss through an energy deficit.
Benefits
Because low-fat diets limit the consumption of unhealthy saturated and trans fats, they can reduce your risk of heart disease and other chronic health conditions. The National Cancer Institute states that low-fat diets can reduce the risk of breast cancer recurrence. Low-fat diets also tend to be high volume due to the bulkiness of fruits, vegetables and grains---meaning individuals can lose weight eating a greater quantity of food each day.
Some low-carbohydrate diets allow liberal use of rich foods limited or eschewed by low-fat menus---including butter, cream, cheese, eggs, cream-based sauces, oily fish and fatty cuts of meat. Individuals who enjoy such foods may find low-carbohydrate diets highly palatable. Additionally, some low-carbohydrate diets---particularly ones that emphasize foods rich in omega-3 fatty acids while limiting saturated fat intake---may have a favorable impact on cholesterol profiles, according to the Mayo Clinic.
Considerations
With both low-fat and low-carbohydrate diets, caloric intake is the ultimate determinant for weight loss. Eating too many calories---whether from low-fat or low-carbohydrate sources---can prevent weight loss or even lead to weight gain. In addition, both diets are most effective when strictly adhered to; straying from the prescribed eating plans can hinder weight loss efforts or cause you to regain lost weight.
Warning
An extremely low consumption of fat may limit the body's ability to carry fat-soluble vitamins and to obtain essential fatty acids---both of which are necessary for maintaining good health. In some cases, low-fat diets may also raise triglyceride levels, leading to undesirable cholesterol ratios in the bloodstream.
According to the Mayo Clinic, low-carbohydrate diets have not been studied for long-term safety and effectiveness; research is limited to the short-term effects. Frequent consumption of foods high in saturated fat and cholesterol, allowed on many low-carb regimens, may increase your risk of heart disease. Consult with your physician before adhering to a very low-fat or low-carbohydrate diet.
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