Why You Should Eat Enough Protein When Dieting and How Much You Need per Day
When people think of dieting, they often focus only on “how little” they eat. But even with the same calories, the results can change greatly depending on “what” you eat. Protein, in particular, is the nutrient you should prioritize most wisely during a weight-loss phase. It helps protect muscle, keeps you less hungry, and even makes your body burn more calories simply through the process of digesting it. Today, we will break down why that matters and how much protein you should eat per day based on your body weight.
| Section | Key summary |
|---|---|
| Introduction | When people think of dieting, they often focus only on “how little” they eat |
| The basic principle of weight loss: a calorie deficit | 1kg of body fat is equivalent to about 7,700kcal |
| Reason 1. It protects muscle and helps preserve basal metabolic rate | Short key point |
| Reason 2. It keeps you full longer | Short key point |
| Reason 3. It has the highest calorie cost for digestion (TEF) | Digesting and absorbing food also requires energy |
| So how much should you eat per day? | Practical method in brief |
| How to apply it to your actual diet | Calculate your target protein amount (body weight × 1.2~1.6g) |
The basic principle of weight loss: a calorie deficit
The principle behind losing weight ultimately comes down to one thing: consistently maintaining a “calorie deficit,” meaning you consume less energy than you use in a day. 1kg of body fat is equivalent to about 7,700kcal. By simple calculation, creating a deficit of 500kcal per day adds up to about 3,500kcal in one week, so you can expect to lose about 0.5~0.6kg of body fat in a month. The key is making sure that within this deficit, you lose fat rather than muscle, and protein is what makes that possible.
Reason 1. It protects muscle and helps preserve basal metabolic rate
When you reduce calories, your body tries to break down not only fat but also muscle to use as energy. When muscle decreases, your basal metabolic rate (BMR), the calories you burn even at rest, goes down, eventually creating a body that “doesn’t lose weight even when eating less.” Enough protein acts like a shield that slows this muscle loss. If you add light strength training as well, the “quality” of the weight you lose changes even with the same deficit.
Reason 2. It keeps you full longer
Among the three major nutrients (carbohydrates, protein, and fat), protein is the one that helps fullness last the longest. It lowers ghrelin, a hormone that stimulates appetite, and supports satiety signals, so even at the same calorie level, a protein-rich meal keeps you less hungry until the next meal and reduces cravings for snacks. In other words, it makes dieting feel more manageable even when eating less.
Reason 3. It has the highest calorie cost for digestion (TEF)
Digesting and absorbing food also requires energy. This is called the “thermic effect of food (TEF).” Carbohydrates are about 5~10% and fat is about 0~3%, while protein is the highest at about 20~30%. Put simply, if you eat 100kcal of protein, about 20~30kcal of it is naturally used during digestion. The effect is not huge, but when it adds up, it clearly helps with dieting.
So how much should you eat per day?
The general recommended protein intake for adults is about 0.8g per 1kg of body weight, but during a calorie-restricted weight-loss phase, about 1.2~1.6g per 1kg of body weight is recommended to protect muscle. For example, if you weigh 60kg, your target is about 72~96g per day; if you weigh 70kg, it is about 84~112g. Rather than eating it all at once, dividing it into 20~35g across three meals is better for both absorption and fullness.
- Chicken breast 100g ≈ about 23g of protein
- 1 egg ≈ about 6~7g
- Half a block of tofu (150g) ≈ about 12g
- Greek yogurt 100g ≈ about 9~10g
- One cup of cooked lentils or black beans ≈ about 15~18g
- Small can of tuna (85g) ≈ about 18g
How to apply it to your actual diet
- Calculate your target protein amount (body weight × 1.2~1.6g).
- At each meal, first fill your plate with a palm-sized portion of a protein side dish.
- Fill the rest of the plate with fiber-rich foods such as vegetables and whole grains to increase fullness.
- Replace snacks like cookies or chips with Greek yogurt, boiled eggs, or a handful of nuts.
- After exercise, especially strength training, make sure to get protein.
- Drink enough water, and record your weight once or twice a week under the same conditions.
Protein makes dieting easier, less painful, and more sustainable. Rather than relying on excessive fasting or extreme meal plans, filling each meal with protein and maintaining a gradual calorie deficit will take you further in the long run. However, this article is for general informational purposes only and is not medical advice. If you have an underlying condition such as kidney disease, or if you are pregnant or breastfeeding, consult a doctor or nutrition professional if possible before increasing your protein intake.