ou gain weight when your total calorie intake exceeds calorie expenditure. Limiting consumption of carbohydrate and fats is considered to be the most effective strategy for curtailing calorie ingestion. By combining appropriate calorie-burning workout with dietary changes you can easily get rid of excess body weight. However, currently there is no consensus about the diet that is best suited for weight loss. While most weight loss diets focus on limited carbohydrate consumption, a number of weight loss programs encourage a fat-restricted diet. However, recent studies claim that neither restricting carbohydrate intake nor limiting fat intake would help unless you know the amount and type of macronutrients that are best for your health. Furthermore, the long-term effect of a particular diet on overall health should be taken into account.
Low Carbohydrate Diet vs. Low Fat Diet on Weight Loss
Though both low carbohydrate diet and a low-fat diet are widely recommended for weight loss, the latest studies have found slight differences in the two major dieting strategies. In a clinical trial, 609 overweight adults from 18 to 50 years of age were divided into two groups. One group was on a healthy low-fat diet and the other group was recommended a healthy low carbohydrate diet. During the first 8 weeks of the trial, participants limited their total fat or digestible carbohydrate intake to 20 grams per day. The low-fat diet group reduced the consumption of high-fat foods such as fatty meats, edible oils, nuts, and whole-fat dairy. The low-carbohydrate diet group was instructed to reduce the consumption of starchy vegetables, rice, grains, cereals, and legumes. From the ninth week, the participants were instructed to gradually increase fat or carbohydrate intake by 5 to 15 grams per day per week until the lowest maintainable level was reached.
Both the groups were encouraged to increase consumption of vegetable and whole foods that are nutrient dense and minimally processed, and preferably home-cooked, and minimize intake of refined flour, added sugar and trans fats. Moreover, participants were advised to continue with their recommended physical activities. At the end of the 12-month study period, no significant difference was observed in the results of the two diets. The healthy low-fat diet group on average lost 5.3 kg whereas the healthy low-carbohydrate diet group on average lost 6 kg 
Low Carbohydrate, High Fat Diet vs. Low Fat Diet on Mortality
A low carbohydrate diet involves limited carbohydrate intake. To meet the body’s calorie requirement, the dieter increases consumption of either protein or fat or both. Though this dieting strategy is known to promote weight loss, studies on the long-term effect of low carbohydrate diet on human health and mortality are confusing.
A study presented at a European cardiologists’ meeting involving a US sample of 25000 people revealed that mortality risk due to any cause was 32% higher in people on a low carbohydrate diet. They have a 51% higher risk of dying from heart disease, 50% higher risk of stroke-related death and a 35% higher risk of cancer deaths. 
Another study conducted by researchers in Harvard found that higher mortality rate was associated with both high and low carbohydrate diet, whereas moderate carbohydrate intake helps in increasing longevity. Carbohydrate intake is said to be moderate when 50 to 55% of the daily energy requirement comes from carbohydrate. In a low carbohydrate diet, less than 40% of energy consumption comes from carbohydrate. In a high carbohydrate diet, more than 70% of the daily calorie intake is provided by carbohydrate-rich foods. Low carbohydrate diets encourage consumption of animal-based proteins and fats such as beef, lamb, pork and chicken. The mortality rate was found to be higher in this group. However, when plant-based food was the predominant source of protein and fats, despite restricted carbohydrate intake, the mortality rate was found to be lower. Sources of plant-based protein and fats included nuts, peanut butter, whole-grain bread and vegetables. Hence, the study suggests that the source of fat plays an important role in determining its exact effect on health. 
However, consuming more than the moderate amount of carbohydrate could be detrimental for the health, and, according to a newer study, higher carbohydrate intake increases the risk of mortality. On the other hand, a higher intake of fat was associated with lower total mortality. The total fat content and the type of fat in the diet did not increase risks of cardiovascular disease and heart attack or mortality associated with cardiovascular disease. Higher saturated fat intake actually appears to help in reducing the risk of stroke. 
Why Low Carbohydrate, High Fat Diet is better than Low Fat Diet
The aforementioned clinical trials lead to the conclusion that though moderate carbohydrate intake appears to be good for health, a fat-restricted diet could wreak havoc on our health. Consumption of dietary fats entails a number of health benefits.
1. Stores Vitamins
Vitamins A, D, E and K, being fat-soluble, are stored in the body fats. A fat-restricted diet tends to deplete your body’s reserve of these important vitamins. To minimize the risk of deficiencies of fat-soluble vitamins, you must add foods rich in healthy fats such as fatty fish, avocado, carrots, and dairy products to your diet.
2. Protects Against Injuries
Fats form a protective cushion around the vital organs such as the liver, kidneys, and heart and also serve as a source of energy for these organs. Visceral fat helps in protecting these organs from injuries. They are known to be a boon for athletes participating in contact sports who have a higher risk of injuries.
3. Helps Maintain Core Temperature
Fat acts as the natural insulator of the body. In cold weather conditions, body fat helps in blocking excess heat loss. It could help in reducing the risk of hypothermia. Few studies have shown that high body mass protects cold water swimmers from hypothermia.
4. Source of Energy
Fat is also a source of energy for the body. The body’s fat reserve helps in meeting the energy demand during stressful situations. It is known to provide energy to older adults who are susceptible to weight loss owing to the aging process. 
5. Supports Healthy Cognitive Function
Fat and cholesterol constitute about 60% of the brain. Almost 25% of body cholesterol is located in the brain. The lipids from the basic framework for the cells that are encased in the lipid-based membranes. Therefore, a fat-restricted diet is believed to affect the health and function of the neurons or brain cells. Apart from helping in maintaining the structure of the brain cells, cholesterol aids transmission of the nerve signals and helps in the storage and retrieval of information. Normal transmission of nerve impulses could be impaired when the cholesterol level is 10% below the normal level. A number of studies have found an association between higher cholesterol level with improved memory and cognition function and lower risk of neurodegenerative diseases such as Alzheimer’s. Dietary fat and cholesterol appeared to inhibit the formation of amyloid plaque, which is the major cause of Alzheimer’s disease. On the other hand, a low-fat diet could accelerate neurodegeneration. 
6. Helps Reduce Cardiovascular Risk Factor
Contrary to popular belief, a low-fat diet may not protect you from cardiovascular disease. In a study, volunteers without clinical cardiovascular disease and diabetes were divided into two groups. One group was on a low carbohydrate diet and the other group was on a low-fat diet. The low-fat diet group obtained less than 30% of their daily calorie requirement from the fat of which less than 7% came from saturated fat. After 12 months, investigators found that the low carbohydrate diet group lost more weight and fat mass than the low-fat diet group. In addition, the high-density lipoprotein (HDL) or good cholesterol level was higher in the low carbohydrate diet group and the triglycerides and total cholesterol level were lower than the low-fat diet group. The study led to the conclusion that a carbohydrate-restricted diet is more effective than a fat-restricted diet in reducing the risk of cardiovascular diseases. 
7. Helps Fight Inflammation
Studies suggest that eliminating fats from your diet could make you susceptible to inflammatory disorders. Low-grade inflammation is found to be a major cause of a number of chronic health disorders. Researchers, while comparing the effect of diet on the inflammatory markers, found that people on high fat low carbohydrate diet had a lower risk of developing low-grade inflammation than those on low-fat high carbohydrate diet. In the clinical study, individuals on high fat low carbohydrate diet obtained 56% calories from fats and 9.6% from carbohydrate and those on low-fat high carbohydrate group acquired 55.7% of their daily calories from carbohydrate and 25% from fats. 
8. Helps Fight Nonalcoholic Fatty Liver Disease
Nonalcoholic fatty liver disease is a chronic liver disorder. Though currently little is known about the effect of diet on liver histopathology in individuals suffering from the fatty liver disease who do not take alcohol, a low-calorie fat-restricted diet is recommended. However, a study has revealed that this dietary recommendation could worsen the liver condition. High carbohydrate intake was found to increase the risk of inflammation, whereas higher fat consumption helped in reducing the risk of liver inflammation in people with nonalcoholic fatty liver disease. 
Best Fat Rich Foods
There are four types of dietary fats – saturated fats, monounsaturated fats, polyunsaturated fats, and trans fats. All types of fats are not created equal. While the industry-made trans fats are harmful for health, the natural dietary fats are known for a number of health benefits. The harmful effect of a high-fat diet is associated with the consumption of trans fats that are produced during the hydrogenation of natural oils. Foods containing hydrogenated vegetable oils contain these harmful fats that increase LDL cholesterol and reduce the HDL cholesterol levels. Trans fat intake increases risks of heart diseases, stroke, insulin resistance and a number of chronic health disorders.
A diet containing a higher amount of unsaturated fats is known to be good for health. Consuming saturated fats in moderation is known to benefit health in various ways. A low-fat diet reduces healthy fat intake that are essential for maintaining a healthy body.
Polyunsaturated fats are primarily found in vegetable oils. They are known to lower unhealthy cholesterol and triglyceride levels that help to reduce the risk of cardiovascular diseases. Omega-3 fat is a type of polyunsaturated fat known for a number of health benefits. Fatty fish such as salmon, mackerel, and trout are excellent sources of these healthy fats. According to the American Heart Association’s dietary guidelines, you can eat at least two servings of fatty fish per week. These healthy fats are also found in walnuts and flaxseeds. Among vegetable oils, sunflower oil, corn oil, safflower oil, canola oil, and unhydrogenated soybean oil contain polyunsaturated fats.
Monounsaturated fats are another type of unsaturated fat that can help in protecting your cardiovascular system. This unsaturated fat is found in abundance in the Mediterranean diet, which is renowned for increasing longevity. Olive oil is an excellent source of monounsaturated fats. They are also found in avocados, almonds, hazelnuts, sesame seeds, cashews, Brazil nuts, pumpkin seeds, canola oil, and peanut oil. Foods rich in monounsaturated fats are also good sources of vitamin E. Common dietary sources of saturated fats are whole milk and whole-milk based dairy products, cheese, red meat, and coconut oil. 
Full-fat dairy is rich in saturated fat that according to studies is good for the cardiovascular system and can help in reducing central obesity or belly fat. Latest studies contradict earlier studies that associated high dairy fat intake with increased risk of heart disease. A long-term study on aged adults above 65 years has revealed that long-term intake of dairy fats did not increase the risk of cardiovascular disease or overall mortality. Instead, a higher level of the saturated fatty acid heptadecanoic acid present in milk fat appears to reduce the risk of cardiovascular disease and stroke-related mortality.  According to a study in Sweden, higher intake of butter as a spread, whipped cream, and high-fat milk helped reduce risk of central obesity. Central obesity was more prominent in individuals who avoided butter and whipped cream and consumed low-fat milk. 
Coconut oil is made up of 90% saturated fats. Despite the high saturated fat content, which is significantly higher than that in butter and lard, consumption of coconut oil is associated with higher HDL cholesterol level. 
According to the American Heart Association’s dietary guidelines, up to 35% of the daily calorie intake can come from dietary fats. For a person on a 2000-calorie daily diet, dietary fat can provide up to 700 calories, which is equivalent to 78 grams per day. It is advisable to limit saturated fat intake to 10% of the daily calorie intake or to 22 grams in case of a 2000-calorie diet.