Fat Loss Diet

Rapid or Moderate Fat Loss?

The question of whether to lose weight quickly or slowly depends heavily on the starting weight. For significant obesity, aiming for only a small calorie deficit of 500 kcal per day is not very meaningful. Therefore, several crucial factors need to be considered: total calorie expenditure, starting weight, and body fat percentage.

You can calculate your body fat percentage here: BFP Calculator
And your total calorie expenditure here: TDEE Calculator 

For example, if the body fat percentage is between 30 and 40% for men or 40% and 50% for women or higher, this requires a correspondingly high daily calorie intake to maintain the current weight. For an average-sized man weighing 130 kg with a body fat percentage of approximately 40%, the total daily energy expenditure (TDEE) could easily be 4000 kcal or more.

Now there are two options: Rapid or  Moderate Fat Loss
For a deficit of 500 kcal, the man would have to eat 3500 kcal a day and would lose about 0.5 kg of fat per week.
For a deficit of 2500 kcal, the man would have to eat 1500 kcal per day and would lose about 2.5 kg per week.

Both approaches will work, but each has its own advantages and disadvantages.

The Rapid Fat Loss Diet is characterized by quick weight loss, which can be motivating, especially for individuals with significant obesity. Regular changes on the scale every few days can provide motivation compared to slower progress. However, it requires strong willpower and perseverance.

The Moderate Fat Loss Diet allows for a slower weight loss but is easier to sustain over a longer period. One advantage is the flexibility for occasional indulgences, as the calorie buffer is more generous. However, for individuals with a very high starting weight and significant obesity, a too low calorie deficit might be demotivating if only minor changes are observed. 

Therefore, it's essential to carefully consider individual needs and goals when choosing a diet.

The following will delve into the extreme variations of both diet forms: Rapid Fat Loss with maximum calorie reduction and Moderate Fat Loss with a higher calorie buffer. There's also the option to find a middle ground and reduce calorie intake according to individual needs.

Rapid Fat Loss with Maximized Caloric Deficit

Rapid Fat Loss Diet, Crash Diet, Mini-Cut or High-Speed Diet – These diet forms have different names but essentially work in the same way. They are based on a significant caloric deficit that forces the body to tap into its fat reserves. These diets enable substantial weight loss in a short amount of time. The diet combines a greatly reduced calorie intake with increased protein consumption to maximize fat loss and minimize muscle loss. Building on this fundamental principle, I have developed a plan that explains how to effectively implement this form of dieting.

How Does This Diet Work?

This form of diet combines aspects of low-fat and low-carb and relies on a high protein content. The main focus is on a significant calorie deficit to promote fat loss.

The higher the body weight, the more effective weight loss is with this form of diet. This is because a larger body mass requires more energy to be maintained. 

If a person's total daily caloric expenditure for weight maintenance is around 4000 kcal and they suddenly only consume 1000 kcal, the sum would be a 3 kg fat loss per week. Instead of aiming for a low caloric deficit of 500 calories per day, it therefore makes sense for severely overweight individuals to choose a diet that allows for quicker weight loss.

However, in principle, this form of diet can be applied by any healthy person. The basic prerequisite is that the body fat percentage (BFP) is not already very low. For men with a BFP below 10% or women with a BFP below 20% this diet form is not suitable. If the BFP is already low and you want to continue losing weight, you should fine tune it with a moderate calorie deficit.

You can also use this diet as a kickstarter to quickly lose a few kilos at the beginning. After a few weeks, you can then switch to a lower deficit. This form of diet (known as a mini-cut) is especially popular among bodybuilders to transition back into the bulking phase more quickly.

High Calorie Deficit
A key component of this diet approach is a high calorie deficit. By reducing calorie intake to a significant level below total calorie expenditure, the body is forced to rely on its fat stores as an energy source. The maximum depth of the calorie deficit depends on individual tolerance and the predetermined protein intake. It is important to find a balanced ratio that allows for effective weight loss while adequately supplying the body with essential nutrients. Each person responds differently to a high calorie deficit, so it is advisable to be mindful of personal limits and listen to one's own body.

High Protein Intake
To exclusively lose fat during the diet and not the hard-earned muscle mass, it is important to maintain a high protein intake. A simple and sensible guideline is to consume approximately 2.5 to 3 grams of protein per kilogram of body weight. This helps preserve muscles, and protein also contributes to satiety. Lean meats and fish are excellent sources to meet the protein requirements during this diet approach. Additionally, supplementing with whey protein powder can be helpful to ensure complete protein intake. As a vegetarian or vegan, you can rely on a variety of soy products to meet your protein needs.

Adequate Vegetable Consumption
Vegetables have the advantage of being low in calories. During this diet, all vegetables that contain less than 5g of carbohydrates and 3g of fat per 100g of raw vegetables can be consumed almost unlimitedly (avocados, for example, are not allowed). Green beans, mushrooms, tomatoes, bell peppers, broccoli, leafy greens, and many other vegetables are ideal for this diet approach. Spices can be added according to taste to enhance flavor.

Sufficient Supplementation
Supplements are useful during this strict diet, especially if it is followed for several weeks. Since dairy products (for calcium), fish (for omega-3 fatty acids), or other foods like whole grains (for essential minerals like potassium, magnesium, zinc) are consumed in limited amounts, it is advisable to rely on dietary supplements. Individual supplements or a well-dosed multivitamin preparation, as well as omega-3 capsules, are beneficial in this regard. For vegetarians/vegans, it is also recommended to supplement iron and vitamin B12 additionally.

Adequate Fluid Intake
Adequate fluid intake is recommended during this diet approach (and in general). It is important to avoid unnecessary liquid calories. Therefore, water, zero-calorie beverages, tea, and coffee without milk and sugar are the recommended drinks. Artificial sweeteners can be used without concern as they are calorie-free and have no harmful effects.

Adjusting the Training
The training can be reduced during this diet approach, if desired. Due to the high caloric deficit, there is no need to additionally stress the body. To preserve muscle mass, it is sufficient to ensure an adequate protein supply and potentially engage in strength training one to two times per week. The intensity should be adjusted to the current condition. Cardio training can also be reduced or temporarily suspended during this time, although it can help increase calorie expenditure and achieve a greater deficit. It is important to pay attention to the signals of your own body and consider how much strain it can handle during this diet approach.

Sweet Treats and Other Low-Nutrient Snacks
This article describes the Rapid Fat Loss Diet in its most extreme form of calorie deficit for maximum weight loss. Naturally, everyone is free to adjust their calorie intake according to their individual needs. If incorporating 200 kcal of gummy bears daily is what helps you stick to the diet, then go ahead and include them. A slightly lower deficit is better than none at all.

How are the progressions going with this diet plan?

During this diet plan, at the beginning, a rapid weight loss of several kilograms within a few days is observed. However, this is not yet fat loss. The initial weight loss is mainly caused by depleting the carbohydrate stores (glycogen) that are bound with water. This can lead to a weight loss of up to 3 kilograms. At this stage, you mainly lose water and deplete the stored carbohydrates.

Over the course of weeks and with the recorded weight progression, fluctuations can be observed, but overall they show a linear downward trend. These fluctuations are irrelevant for the success of the diet.

After reaching the target weight, one should expect to gain back a few kilos, as the stores will refill, as previously mentioned.

Health Aspects

Of course, this diet assumes that you are free from diseases and that your health is in balance. To effectively and healthily lose weight, it is crucial to follow the guidelines in this guide precisely. Make sure to consume an adequate amount of micronutrients and protein. You don't need to worry about myths like a sluggish metabolism or the yo-yo effect. Always remember: the real danger is lingering in the overweight range for too long. The faster you reach a healthy weight, the better.

Fine-Tuning with a Moderate Calorie Deficit

A moderate calorie deficit diet is just as effective for fat loss as the Rapid Fat Loss Diet. Unlike rapid diets, this approach focuses on maintaining a more moderate calorie deficit, meaning consuming slightly fewer calories than your body needs for daily operations. This allows for steady weight loss over an extended period without subjecting the body to extreme stress.

If your body fat percentage is already low, this method is particularly suitable for fine-tuning your diet. It also emphasizes an increased protein intake, though it can be slightly lower compared to the Rapid Fat Loss Diet.

Depending on the TDEE, here, 1 kg of fat loss or more per week is still possible, especially for larger men benefiting from a generally higher calorie expenditure compared to women. Note that as you become leaner, your TDEE will decrease more significantly, and further adjustments may be necessary.

How Does This Diet Work?

In this diet, you opt for a calorie deficit of approximately 500 to 1000 kcal below your TDEE. Set your protein intake between 2.3 to 2.8g per kg of body weight. Ensure a minimum fat intake of around 1g per kg of body weight. The remaining available calories can be fulfilled through carbohydrates.

If, for instance, your TDEE is 2500 kcal, and you save 500 kcal per day, you can expect a weekly fat loss of about half a kilogram.

And remember: Nothing is set in stone. You are not committed to following either the Rapid Fat Loss Diet or the Moderate Fat Loss Diet. You can also choose a middle ground between the two or vary your nutrition from day to day.

Advantages of a Moderate Fat Loss Diet

This diet provides greater sustainability as it is generally easier for most people to adhere to compared to a rapid fat loss diet. While the Rapid Fat Loss Diet may deliver quicker results, it is unfortunately more prone to setbacks. With the Moderate Fat Loss Diet, you have more flexibility for foods with lower micronutrient content, as you choose your calorie target only slightly below your TDEE. Moreover, you will experience more energy in your daily life compared to a diet with a larger calorie deficit.

Refeed Days

Refeed days are an essential part of any diet. The larger the calorie deficit, the more crucial refeed days are recommended. During refeed days, carbohydrate and calorie intake are temporarily increased to give the body a break from the calorie deficit. When entering a calorie deficit, the body responds with various adaptive reactions aimed at slowing down further weight loss. However, this does not mean that the metabolism has come to a halt. The purpose of these adaptive reactions is to reduce energy expenditure to protect the body from further energy deprivation. During this diet approach, there is a reduction in leptin levels, which is responsible for feelings of satiety. At the same time, cortisol levels increase, which is associated with stress reactions. And the production of the active thyroid hormone T3, which regulates metabolism, is also somewhat reduced. These changes can have an impact on appetite, mood, and energy expenditure. Refeed days during this diet approach can help mitigate these adaptive reactions of the body.

(Not to be confused with cheat days, where one indulges unrestrictedly and consumes excessively high calories, which has the potential to hinder diet progress and nullify the calorie deficit.)

Here's what a refeed day looks like:

• Protein intake can be slightly reduced to approximately 1.5 to 2 grams per kilogram of body weight.

• Carbohydrate intake is significantly increased to approximately 4 to 8 grams per kilogram of body weight. The exact amount can be adjusted based on total calorie expenditure. On this day, there is little to no calorie deficit.

• Fat intake remains reduced and is not increased for the refeed day.

Ideally, a refeed day should be implemented once a week. It is recommended to plan the refeed day on a training day to support the body with additional carbohydrates and replenish its energy reserves.

Fluctuations in Weight Loss

Weight loss is rarely a linear process, and it's entirely normal for your weight to fluctuate from day to day. You shouldn't get discouraged if you see a few extra grams on the scale one morning. These minor fluctuations can be caused by factors such as water retention, stomach contents, or hormone levels.

To get an accurate picture of your progress, it's advisable to weigh yourself daily at the same time. Even if there are days when you notice a higher weight, it's important to keep an eye on the long-term trend. If your weight is decreasing overall over weeks and months, you are on the right track.

Maintain the Weight

After achieving your goal weight and aiming to maintain it, you gently approach your new TDEE. Since you're no longer aiming for a calorie deficit, this means you can now eat a bit more to reach maintenance calories. Keep in mind that you'll never hit this exactly, and your calorie intake may always be slightly above or below. Remember the rapid weight loss due to water and glycogen storage at the beginning of the diet? These stores are now replenished. So, don't be surprised if the scale shows two to three kilograms more – that's not body fat. In the following weeks, you maintain your diet with the new maintenance calories and adjust the calorie intake as needed.

Closing Words

Rapid fat loss is possible, but it is important to take the right approach. Crash diets can be effective for losing weight quickly, but they require discipline and attention to proper nutrition. If this is not for you, then opt for a moderate calorie deficit.

Update Status:
Originally created post: 07/2018
Last updated: 05/2023