If you’re interested in trying intermittent fasting, you might have wondered how it compares to other diets. You might also have some questions regarding intermittent fasting if you haven’t heard much about it before, such as: what makes intermittent fasting different from other diets? Is it better than other diets? How effective is it for weight loss? Is it easy to follow?
Every diet is different. Some focus on reducing your appetite, while others restrict calories, and dietary ‘macros’ like carbs, or fat. However, no one diet is best for everyone — what works for you may not work for someone else.
Because intermittent fasting is less a diet, and rather a lifestyle, you can couple it with a diet. Experts do, however, advise that if you do pair intermittent fasting with another diet that you choose one that focuses on eating healthy food and reducing carbohydrates.
So how do the different diets compare to intermittent fasting?
Low-carb diets are popular for weight loss. Though there are a lot of different low-carb diets out there, they all have one thing in common; restricting carbohydrate intake, in some cases to as little as 20-150 grams per day.
This diet’s main aim is to force your body to utilize your fat for fuel instead of carbs as your primary energy source. Fatty acids are moved into your blood and transported to your liver, where some are turned into ketones. Ketones and fatty acids are then used as your body’s primary energy source instead.
This diet has had some profound results in weight loss, especially in patients that were overweight or obese [1-3]. It seems to be particularly effective at reducing dangerous visceral fat, which can become accumulate around your organs .
Low-carb diets have other health benefits related to blood triglycerides, cholesterol levels, blood sugar levels, insulin levels, and blood pressure [5-8]
However, some people may experience an increase in “bad” LDL cholesterol . In extremely rare cases, nondiabetic ketoacidosis could occur, which could be fatal if left untreated .
A low-fat diet restricts your consumption of fat to around 30% of daily calories, whereas an ultra-low-fat diet only allows for a fat percentage of under 10%. This diet is typically mostly plant-based with a limited amount of animal products . This means that it is a diet that is very high in carbs (roughly 80% of calories) and low in protein.
This diet has had a lot of success in weight loss for obese individuals [12, 13]. However, studies have shown that this method is less effective for weight loss in the long term.
Evidence shows that this dieting method can be helpful in improving heart health, including factors such as high blood pressure, high cholesterol, and inflammation markers [14-17]. Surprisingly it can also lead to improvements in type 2 diabetes [18, 19] and slow the progression of multiple sclerosis (an autoimmune disease) .
On the downside, restricting fat intake can cause problems in the long run. Fat has an important role to play in aiding cell membrane growth and hormones.
The Atkins Diet
The Atkins diet involves eating as much protein and fat as you’d like, while avoiding carbohydrates.
It has 4 phases: The first is an induction phase, where you eat under 20 g of carbs for 2 weeks. The remaining phases involve slowly introducing healthy carbs back into your diet as you near your ideal weight.
Many studies found that it leads to faster weight loss than low-fat diets [21, 22]. It is especially successful in reducing stubborn belly fat [23-25].
Similar to other low-carb diets, the Atkins diet has shown success in reducing many risk factors for disease, such as blood triglycerides, cholesterol, blood sugar, insulin resistance and sensitivity, and blood pressure [26-30].
Though the Atkins diet is safe and healthy for most people, there might be some unpleasant side effects. As your body switches to fat as a fuel source, involving ketosis, you may experience typical ‘keto flu” which involves fatigue, nausea, headaches, and brain fog. Some report that this diet can be hard to adhere to.
The Dukan Diet
The Dukan diet is a high-protein, low–carb weight loss diet that has 2 weight loss phases and 2 maintenance phases. The length of each phase is determined by the amount of weight you want to lose.
The weight loss phases involve eating unlimited high-protein foods. The maintenance phases involve adding non-starchy vegetables, some carbs, and fat. As you progress, pure protein days will become less and less to maintain your new weight.
Many studies show this diet to be effective in weight loss [31-34]. This is purportedly due to increased metabolic rate, a decrease in ghrelin (the hunger hormone), and an increase in fullness hormones [35-38].
On the downside, there is very little quality research available on the Dukan diet. The Dukan diet limits both fat and carbs — a strategy that is not clearly supported by peer-reviewed science. What’s more, fast weight loss achieved by severe calorie restriction tends to be accompanied by significant muscle loss .
These factors, in conjunction with severe calorie restriction may also cause your body to conserve energy, leading to rapid regaining of lost weight .
The HCG diet
The HCG diet (HCG stands for Human Chorionic Gonadotropin, a type of hormone) is a very extreme weight loss diet. It is meant to cause weight loss of up to 0.45-1 kg per day.
It is typically split into three phases:
Step 1 involves taking HCG supplements.
Step 2 is an ultra-low-calorie diet of only 500 calories per day, along with HCG supplement drops, pellets, injections, or sprays. The duration of this phase is 3-6 weeks at a time.
In stage 3, you stop with the HCG supplements and slowly increase your food intake.
Though this diet does cause weight loss, studies have shown that the weight loss is solely attributed to the ultra-low-calorie diet, and not the HCG hormone [41-44].
Aside from weight loss, no other benefits have been documented. There are, however, numerous cons associated with this diet, such as muscle loss, headaches, fatigue, and depression. There have also been reports of blood clots likely originating from the diet .
What’s more, the FDA does not approve of this diet, labeling it as dangerous and illegal .
The Zone Diet
The Zone diet is a low-glycemic-load diet, which limits carbs to around 35-45% and protein and fat to 30% of your daily calories. If you follow the diet, it is recommended to eat carbs with a low glycemic index (GI). The idea behind the Zone diet is to balance each meal with 1/3 protein, 2/3 colorful fruits and vegetables, and a little bit of fat (e.g. monounsaturated oil, such as olive oil, avocado, or almonds).
The weight loss results in studies are a bit contradictory. Some claim that the diet promotes weight loss and suppresses appetite, whilst other studies report very little weight loss compared to other diets [47-50].
In terms of benefits, the diet seems to help reduce risk factors related to heart disease and lower chronic inflammation in an overweight individual with type 2 diabetes [51-53].
One downside to this diet is that it limits the consumption of healthy carbs, such as bananas and potatoes.
The Paleo Diet
The paleo diet emphasizes the consumption of whole foods such as lean protein, vegetables, fruits, nuts, and seeds, and to avoid processed foods, such as sugar, dairy, and grains. The theory is that many modern diseases can be linked to the modern Western diet.
More flexible versions of the paleo diet allow for foods that contain dairy, such as cheeses and butter. They also allow tubers like potatoes and sweet potatoes.
In terms of weight loss, several studies have proven that the paleo diet can cause significant weight loss [54-56]. This is thought to be because paleo dieters eat fewer carbs, and more proteins, and reduce their calorie intake by 300-900 calories per day. This diet has shown some good results in terms of other health benefits; it seems effective in reducing risks related to heart disease, for example, cholesterol, blood sugar, blood triglycerides, and blood pressure [57-59].
Similar to other diets that exclude food groups, one possible downside of this diet is that it eliminates whole grains and legumes which are generally considered as healthy and nutritious.
The Vegan Diet
The vegan diet is another diet that is very popular in today’s day and age. This diet restricts all animal products for reasons that could be ethical, environmental-related, or health-related.
In addition to eliminating meat, the vegan diet also eliminates any animal products, which include dairy and eggs, and animal-derived products, such as gelatin, honey, albumin, whey, casein, and some forms of vitamin D3. In essence, vegans use plant-based products as their sole source of nutrients.
In terms of weight loss, the vegan diet seems to be very effective. In fact, the vegan diet is linked to lower body weight and BMI compared to other diets [60-63].
Plant-based diets are also associated with a reduced risk of heart disease, type 2 diabetes, and premature death [57-60]. What’s more, limiting processed meat may reduce your risk of Alzheimer’s disease and dying from heart disease or cancer [64-67].
On the downside, vegans may experience some nutritional deficiencies, such as vitamin B12, iron, calcium, zinc, and possibly omega-3 fatty acids [68-73].