If you’re trying to lose weight, adding more protein to your diet may help you take in fewer calories. Studies show protein is the most satiating of the three macronutrients, and consuming more protein can reduce the number of calories you eat at a subsequent meal. In fact, when protein enters your digestive tract, it turns on appetite-suppressing hormones, like GIP and GLP-1, more than fat and carbohydrates do. Studies show an increase in satiety with diets where protein makes up 25% of calories and higher.
In addition, diets higher in protein modestly boost your metabolic rate. One component of metabolism is the thermic effect of food, the extra energy you expend to digest and process the food you eat. The thermic effect of food makes up about 10% of the calories you burn on a given day. Increasing the protein content of a diet boosts this value slightly. That’s why you hear dietitians and trainers recommending protein at every meal for people who are trying to lose weight. However, you have to consider any dietary component within the context of the bigger, metabolic picture. As a new study shows, downing a high-protein meal with a sugar-sweetened drink might destroy the fat loss benefits of that meal. Here’s why.
Soft Drinks and Burgers Don’t Go Together
In a new study published in BMC Nutrition, researchers looked at the impact of consuming a meal high in protein, in this case, a burger, with a sugar-sweetened drink. What’s the beverage most people drink with a burger, whether it be a beef burger or a veggie burger? A soft drink! Soft drinks and fast food burgers go together and it’s an unhealthy partnership.
In the study, researchers asked the participants to live and sleep in a metabolic chamber for 24 hours. In a metabolic chamber, researchers are able to measure carbon dioxide and oxygen and determine what macronutrients the body is using as well as how their metabolic rate responded to particular meals.
The participants visited the chamber on two separate occasions and ate one of two diets, one consisted of 30% protein, a high-protein meal. The other was a 15% protein meal. After the meal, they washed it down with a beverage that was either artificially sweetened or sweetened with sugar. What they found was drinking a beverage sweetened with sugar suppressed thermogenesis and reduced the breakdown of fat. The sugar-sweetened drink put a brake on the use of fat as a fuel source. In fact, with the high protein meal, it suppressed fat utilization by 40%. That’s not what you want if you’re trying to shed body fat.
Another Reason More Protein is Better for Weight Loss
We know that consuming more protein helps with weight loss by suppressing appetite and slightly boosting thermogenesis in response to a meal, assuming you don’t wash it down with a sugary drink. But there’s another reason you need more protein when you’re trying to lose weight, especially if you’re over the age of 50. If you restrict calories to lose weight, especially later in life, you lose not only body fat but lean body tissue as well. But, you want to hang on to your muscle to avoid sarcopenia. Studies show that consuming a higher protein diet leads to less loss of lean tissue when restricting calories. So, a diet that contains more protein when losing weight is important for body composition as well.
The degree of satiety you get with a high-protein diet is substantial. Two studies published in nutrition journals showed that participants who replaced carbohydrates with protein ate between 200 and 400 fewer calories daily. Over time, that could lead to substantial weight loss. If you want to eat less, make sure you’re consuming a protein source at every meal.
What is a High-Protein Diet?
Standard high-protein diets usually consist of 25% to 30% protein, 40 to 45% carbohydrates, and about 30% fat. If you work out or strength train, you might be getting around this amount anyway and this range is ideal for preserving lean body mass when you’re trying to lose weight. Even if you eat a higher protein diet to lose weight, make sure you’re getting enough fruits and vegetables for fiber and for additional vitamin and minerals. Most people don’t get enough fiber in their diet, particularly those who eat a high-protein diet. Certain types of fiber are important for cultivating healthy gut bacteria, a key component of digestive and immune health. Plants are also a substantial source of phytonutrients that you don’t find in animal foods. Most Americans don’t get enough plant-based foods on a daily basis.
Don’t forget that many plants are also a viable source of protein. Edamame, tofu, tempeh, whole grains, beans, lentils, nuts, and even some vegetables contain substantial quantities of protein in combination with fiber. Due to their fiber component, these foods can also help suppress your appetite. Protein is even more important if you exercise. You’re already aware that you need protein to build muscle but you also need it if you do endurance workouts since during sustained periods of endurance exercise can lead to oxidation of amino acids from protein, especially if you’re eating a low-carb or low-calorie diet.
The Bottom Line
If you’re trying to lose weight, protein is your pal. Enjoy a diversity of protein sources, including plant-based ones, but don’t reduce the benefits by washing them down with a sugary beverage – and that includes soft drinks and fruit juice. Sugar has no nutritional value and is linked with health problems, like obesity and heart disease. Even fruit juice is a concentrated source of natural sugar that can rapidly spike your blood sugar. Stick to sugar-free beverages and don’t be afraid to reach for a glass of the universal beverage, water.
Forbes.com. “This is Why Drinking a Soda with Your Big, Juicy Hamburger is a Really Bad Idea”
BioMed Central. “Sugar-sweetened drinks and your metabolism”
Nutr Metab (Lond). 2014; 11: 53.Published online 2014 Nov 19. doi: 10.1186/1743-7075-11-53.
Physiol Behav. 2008 May 23;94(2):300-7. doi: 10.1016/j.physbeh.2008.01.003. Epub 2008 Jan 12.
Today’s Dietitian. Vol. 12 No. 2 P. 34. February 2010.