The Millennial Nutritionist

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How Does Increasing Protein Intake Affect Weight Loss?

Written by Jordyn King, BS, MS

As a nutrition professional, I would argue that protein is the most important macro for long term weight loss. A high protein intake boosts metabolism, reduces appetite and changes weight-regulating hormones. Three different mechanisms of protein can help you lose weight and even belly fat. In order to determine when and how much to eat; your body goes through different kinds of brain signals and hormones that can change your response to feeding mechanisms. Through a higher protein intake, it actually increases levels of satiety hormones of the GLP -1, peptide YY and Cholecystokinin. Thus, leading to an automatic reduction in calorie intake. By replacing carbohydrates and fat intake with protein, you are more likely to reduce the hunger hormones in order to boost your metabolism. Increasing your protein can be simple; however, it’s not just eating more meat, it is more about consuming protein rich foods. These protein rich foods can include meat, fish, eggs, dairy products, vegetables, and legumes (including kidney beans or chickpeas). Also, consuming protein supplements can increase your protein intake (such as whey protein powder). 

Thermic Effect of Food (TEF)

Through your digestive tract and metabolism of protein intake, some calories can be used for the purpose of digesting and metabolizing the food which is termed as the “Thermic Effect of Food”. The body can use up to 20-30% of its protein calories to be burned off in the body while it is still digesting and metabolizing. Thus, TEF is the energy that you consume to metabolize and digest food over a 24 hour period. The thermic effect of food and energy expenditure in protein (20-30%) is three times higher than the thermic effect of carbohydrates (5-15%) and fat (3%) content. The TEF is a reason you should include protein in each meal and why it's important in promoting long term weight loss. Additionally, a higher protein diet has been shown from research to boost metabolism and increase the amount of calories burned by a total of 80 to 100 calories per day. 

Feel Fuller for Longer 

Protein can also help reduce hunger and appetite through several different mechanisms meaning you end up eating fewer calories without having to account for the calories or consistent control portions compared to a lower protein diet. Interestingly, protein can cut cravings or reduce the desires for late night snacking. Late night snacking can be one of the biggest challenges of why people fail on their diet or maintain healthy food habits in the process of losing weight. Thus, maintaining a higher protein intake should make it easier to stick to a healthy diet and resist the cravings of late night snacking.   

Protein can Increase Muscle Loss and Increase Metabolism 

Protein can prevent your body from going into muscle loss or slowing down your metabolism. In general, when individuals lose weight, muscle mass will decrease over time. However, the goal of weight loss is to lose body fat which is both subcutaneous fat (under the skin) and visceral fat (around the organs). Losing muscle mass is a common side effect of weight loss that most people do not desire. Another side effect of losing weight is that your metabolism tends to decrease allowing you to eat less. This is often referred to as starvation mode and can amount to several hundred fewer calories burned each day. Thus, an individual can still gain muscle mass and boost metabolism while still the unwanted body; however, it's important to increase your daily protein intake and stay moderated in your carbohydrates and fat intake in each meal. 

So how much protein should we be eating throughout the day? 

From the dietary reference intake for protein is only 46 to 56 grams for the average women and men for weight maintenance. This amount is low if you were trying to lose weight or gain muscle. Most often it is simple to include a protein for each meal such as one chicken breast. As a nutritional professional, it is best to spread your protein intake throughout the day by eating protein every meal and even in your snacking periods. Thus, in order to lose weight aiming for around 25% to 35% of calories as a protein may be optimal which is around 100-150 grams of protein a day. However, providing 20-40 grams of protein per meal time will induce both satiety and fullness to your body. 

In conclusion…

The majority of studies that I have looked at show that a higher protein diet (or intake) leads to significant long-term weight loss. A higher protein intake and diet is also associated with maintaining less belly fat which can build up around the internal organs and cause underlying diseases. Keep in mind, weight loss is not the most important factor of maintaining a high protein diet, it is to keep off the weight long-term which really counts. Also remember, you don’t need to restrict anything including carbohydrate and fat intake to benefit from a higher protein intake. Thus, adding in more protein to your diet is the simplest way to lose weight long term. Remember, the amount of protein you need depends on your individual weight, goals and lifestyle. 


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