Can proteins help to shrink belly fat? 5 ways it can and 8 protein sources to support belly fat loss
Updated: Dec 4, 2022
We hear and read a lot about carbohydrates and fats but not as much about the third source of macronutrients, proteins. Yet they are as essential for health and balance as are the other two. What is protein? What are the signs of protein deficiency? How much protein is needed to prevent deficiency? Can protein intake support weight and fat loss goals? And what sources of protein are the best? We'll address these questions below.
What is protein?
Protein is a key part of any diet and is found in every part of the body. It is the building block of muscles, skin, hair, bones, enzymes and hormones and it plays an essential role in all body tissues (Atli Amarson, 2017)
Protein is perhaps the most important nutrient for weight management.
"[Protein] makes up the enzymes that power many chemical reactions and the hemoglobin that carries oxygen in your blood. Protein is made up of twenty-plus basic building blocks called amino acids." Nine of these amino acids are essential, which means that we must obtain them from food. The body can make the rest "either from scratch or by modifying others" (Harvard School of Public Health).
What are the signs of protein deficiency?
Protein deficiency is rare in western countries but it can still happen especially among the old. Protein deficiency can have severe health implications including:
· Fatty liver (a common condition in obese people)- may be due to "impaired synthesis of fat-transporting proteins known as lipoproteins"
· Skin degeneration, flaky, splitting, redness or patches of de-pigmented skin.
· Hair thinning and brittle nails
· Increased severity of infections
· Failure to grow (or stunting)
· Loss of muscle mass (muscle wasting)
· Increased risk of bone fracture
· Decreased immunity
· Weakening of the heart
· Weakening of the respiratory system
· May increase appetite and promote overeating
· Swollen and puffy skin, and a bloated belly (all signs of kwashiorkor-the most severe form of protein deficiency)
Because the liver and kidneys play key roles in the metabolism of proteins, overconsumption can lead to "protein poisoning, due to increased levels of ammonia, urea and amino acids in the blood" (Atli Amarson, 2017)
How much protein is needed to prevent deficiency?
It depends on many factors including age, physical activity level, body weight and muscle mass.
Therefore, there is no general consensus on how much protein is needed for overall health and balance. Some recommend 1 gram of protein per pound of lean body weight, others give a range between 10% and 35% of calories per day:
"For optimal recovery from training, satiety, and a healthy body, 1 gram of protein per pound of lean body weight is a pretty good guideline" (Matt Dustin, 2017).
There is a wide range for "acceptable protein intake - anywhere from 10% to 35% of calories per day" (The National Academy of Medicine).
"[A]n average of 7 grams per day for every 20 pounds of body weight" is considered adequate. (Harvard School of Public Health, 2022).
Can protein intake support fat loss goals?
To lose excess body fat, many approaches have been advocated for. Not all strategies are effective nor do they always bring lasting results. For example, cutting calories and spending more time exercising can help to lose weight, but this can also result in a loss of muscle mass, an undesirable outcome. Starving yourself and exercising until you drop are neither a sustainable nor a healthy way to lose weight or belly fat. Below are five ways that protein can help:
1. Prevent muscle mass decline: As people age, they start losing muscle mass. As much as 30-50% decline in muscle mass has been reported in populations between the ages of 40 and 80. To maintain muscle mass may require an increase in protein intake as the same amount needed in younger years may no longer be sufficient later in life (Marta Lonnie et.al. 2018).
One of the benefits of a higher protein diets include "...improvement in muscle mass... achieved by activation of muscle protein synthesis …." according to Flor E. Morales et. al. (2017).
“For individuals who have more fat to lose, reducing calories by 30-40% while increasing protein intake to 0.55-1.4 grams per pound (1.2-3.1 g/kg) may maximize fat loss while promoting muscle mass maintenance” Jillian Kubala (2018)
2. More calories are burned to process protein: Protein is known to be more satisfying than the other two macronutrients, namely carbs and fat. "[Y]our body... burns more calories processing protein than these other nutrients (Marta Lonnie et.al. 2018 and Jillian Kubala, 2018).
Protein has a high thermic effect, which is the percentage or total amount of calories burned while the body is digesting and metabolizing the protein. This can be as high as 20-30% which is much higher than the 5-10% for carbs and 0-3% for fat (Kris Gunnars, 2017).
3. Improving body composition: Two studies funded by the National Institutes for Health note that increasing protein intake to at least 0.64g per pound (which is the same as 1.14 grams per kilogram of body weight) may improve your body composition in favor of losing fat and gaining muscle mass. In one of the studies, which focused on 88 overweight adults, a hypocaloric diet that contained 0.64 grams per pound (1.4g/kg) of body weight was more effective in preserving muscle mass and reducing body fat than a diet providing 0.36 grams per pound (0.8 g/kg) of protein (Tang 2013). In short, [a] diet high in protein facilitates fat loss while supporting muscle growth" (Kubala 2018).
4. Supporting natural body detoxification: Proteins are needed "for the enzymes that help your body detox naturally" (WebMD 2022). Toxins build up in fat cells and often, what looks like excess fat around the belly is an accumulation of toxic waste that must be released and removed from the body. Once this is done, not only will it result in weight loss but also in fat loss. A sufficient consumption of protein supports body detoxification.
5. Protein increases appetite-reducing hormones: "By replacing carbs and fats with protein, you reduce the hunger hormone... This results in an automatic reduction in calorie intake." (Kris Gunnars, 2017). Since excess calorie is a key factor in weight gain and fat buildup, any way to reduce calorie intake without feeling deprived can serve many purposes including fat loss.
The source of protein matters however. In my experience, legumes including beans, lentils and chickpeas are less satisfying than proteins from animal sources such as eggs, fish, or chicken. I only occasionally eat red meat. These animal sources of protein do not raise blood sugar fast, and with a family history of type 2 diabetes, I am always careful about what I eat that could have a direct or even a delayed impact on my blood sugar levels. Nonetheless, I skip meat or chicken when I cannot trust the quality of the meat. Salmon and sardines are my two favorite types of fish. Otherwise, even when I have beans as my protein source, adding a handful of nuts such as almonds or seeds such as pumpkin seeds or a boiled egg increases my protein intake without the added effect on blood sugar.
If you are in good health and do not have type 2 diabetes or a family history of diabetes, a plant-based source of protein such as beans and lentils may work great for you. There is more and more evidence that a plant-based diet is healthier than a diet that includes foods from animal sources, especially when the animals were not fed a clean natural diet. According to researchers at the Harvard School of Public Health, "it's the source of protein that matters." Proteins that are also good sources of fiber such as beans, lentils and peas can increase the feeling of fullness which "may lead to better weight management and weight loss." After following the diet and lifestyle of over 120,000 men and women for up to 20 years, the Harvard School of Public Health researchers came to the conclusions that: "Those who ate more red and processed meat ... gained more weight, about one extra pound every four years, while those who ate nuts over the course of the study gained less weight, about a half pound less every four years." Also associated with greater weight gain was consumption of chicken with skin and regular cheese whereas nuts, yogurt, chicken without skin, low-fat cheese and seafood "was associated with less weight gain" (Harvard R.H. Chan School of Public Health, 2022)
Therefore, increasing protein intake can support those who are trying to gain muscle or lose fat but the source of protein is an important factor as well because some source can promote fat loss while others are associated with weight gain and muscle loss.
What are the best sources of protein?
Below are 8 food sources of protein that you can enjoy regularly. Each protein source provides a specific amount of protein (Brown, 2017). Paying attention to your body's protein requirements will support your balance.
· Eggs: 6 grams of protein in 1 large egg
· Nuts: 6 grams of protein in 1 ounce (28 grams) of almonds
· Chicken breast: 43 grams of protein in 1 chicken breast, cooked
· Lean beef: 22 grams of protein in 3 ounces (85 grams)
· Fish: 12 grams in 1/4 cup (63 grams) of salmon
· Quinoa: 8 grams of protein in 1 cup (185 grams), cooked
· Lentils: 18 grams of protein in 1 cup (198 grams), cooked
· Yogurt and cheese (if you digest dairy).
The good news is that food sources of protein are readily accessible in most parts of the world. However, while relatively cheap meat, chicken and fish are available in the West, it is not as easily accessible to people with limited resources in the southern hemisphere. Knowing which sources of protein are available and making them a priority in meal planning is an important step in efforts to eat right to shrink belly fat.
When possible, and to fill protein intake gaps, supplementing with quality protein powders is a reasonable option. This can be a suitable short-term solution for example when traveling, or whenever access to protein is limited. Be wise about choosing protein powders though, because some contain too much added sugar and/or other unwanted ingredients (Gavin Van de Walle 2022). Pea and hemp proteins are my favorite. They can support your protein requirements for a healthy weight and waistline. Whey protein can serve the same purpose, if you can digest dairy. Many protein powders provide around 20 grams per serving.
Other steps known to support fat loss include:
· Cutting back or giving up highly processed foods
· Reducing overall calorie intake
· Temporarily giving up all grains
· Increasing fiber intake
· Getting enough sleep
· Lowering stress
· Muscle-building, strength-training exercises (Kubala 2018, Kadende-Kaiser 2020).
In a different blog post, I discuss how fiber can help you lose fat as well. Check it out here and feel free to leave a comment.
While proteins alone are not sufficient to shrink your belly fat, they can be the missing link if you have tried to cut calories and do more exercise but remain disappointed with your results. In my book, Belly Fat in Midlife, I discuss in detail six of the most important steps you need to take if you want to shrink belly fat and keep it off. You can order your copy here.
Your level of commitment will determine the results. One approach alone may not work, but taken together, they will improve results in weight loss and shrinking belly fat. A diet that manages overall calorie intake and pays attention to protein intake, as well as exercise that builds muscle mass will get the ball rolling in the right direction. There is nothing more motivating than seeing yourself in the mirror and being happy with what you see after you have tried these strategies.
Interested in learning more about how to shrink your stubborn belly fat? Grab a copy of my book, Belly Fat in Midlife, here. It's full of relevant dietary and lifestyle choices that will guide you along your journey to shrink belly fat and achieve a healthier balance.
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