What fiber and protein have to do with weight loss
Social media over the years has pivoted from promoting low carb, paleo and keto diets to now being high protein and fiber obsessed. For those who come from a creditable nutrition background, it's exciting that we're shifting to more actionable and sustainable advice. But many are still unaware the "why" behind the reason protein and higher fiber intake can assist with achieving their goals.
Why Fiber should be your best friend
Let's start with what fiber actually is and what it does. Fiber is a unique type of carbohydrate that, unlike other macronutrients, is not fully broken down and absorbed by the body. Instead, it moves through the digestive tract largely intact. Learn about the two different types of fiber and best sources in this helpful article.
Many of us connect fiber with our digestive system, but that's not the only benefit it provides. It's been shown that a higher intake of dietary fiber is associated with a reduced risk of several chronic diseases, including heart disease, cancer, and type 2 diabetes. It's been found that it reduces your absorption of glucose, and LDL cholesterol ("bad"cholesterol), has immune benefits, traps bile and cancer causing substances, and lowers inflammation (1).
Think of fiber as a brush, going down your digestive tract to help clean things up, scrubbing the intestinal walls and helping to clean out waste
Many of us connect fiber with our digestive system, but that's not the only benefit it provides. It's been shown that a higher intake of dietary fiber is associated with a reduced risk of several chronic diseases, including heart disease, cancer, and type 2 diabetes. It's been found that it reduces your absorption of glucose, and LDL cholesterol ("bad"cholesterol), has immune benefits, traps bile and cancer causing substances, and lowers inflammation (1).
How does it help with weight loss?
In several studies, high fiber intake has been tied to significant reductions in body weight due to it's ability to make one feel satisfied and more full. Fiber adds bulk to your food, which can make you feel like you're eating more than you actually are. Fiber also slows down digestion, allowing you to feel fuller longer (2). When you eat foods like pasta or rice, your body breaks them down quickly, causing a fast spike in blood sugar. But fiber-rich foods slow down digestion since they have fewer digestible carbs, leading to a steadier and lower rise in blood sugar.
Aim to get: 25g or more of fiber a day for women and 30g or more of fiber for men
Protein isn't just for the gym bros anymore
Before I studied nutrition, I probably got about 30-40g of protein a day. I would start my day with one egg on toast and thought I was eating a high-protein diet. Little did I know I was eating 6g of protein for breakfast and wondering why I was hungry in an hour. After learning that my exercise level required me to eat at least 0.8-1.0g of protein/kg (your weight in lbs/2.2), my energy levels increased and my recovery post-workout improved drastically.
How can protein help with weight loss?
When losing weight, we often feel hungry and depleted as we start to eat less than what we typically eat. Since we're already eating less, it's helpful to eat foods that make us feel more satisfied and full just as I mentioned above for fiber. In a study, measuring satisfaction levels of different kinds of foods, protein-rich food received the highest ratings, followed by carbohydrate-rich and fat-rich foods (3). High protein meals can also lower ghrelin levels, which can reduce hunger and increase fullness. Ghrelin is a hormone produced in the stomach that signals the brain when it's time to eat (4).
Protein has also been studied to increase diet-induced thermogenesis which is when your body increases its energy expenditure (calories burned) in response to a meal. A high protein diet can induces a negative energy balance (or a deficit)—a state of greater calorie output than input—by increasing diet-induced thermogenesis and sleeping metabolic rate (5).
Protein paired with strength training is another great mix for weight loss as both increase your metabolic rate, and protein post-workout will improve recovery by helping you build muscle mass.
Protein + Fiber = Optimal Results
Now that we've discussed how protein and fiber individually support weight management, it’s easy to see how combining them in meals can be even more effective. By cooking and preparing meals with fiber-rich plant-based foods like beans and legumes, you get the best of both worlds, as they are naturally high in both protein and fiber.
Another great way to boost your protein and fiber intake is by swapping simple carbohydrates like rice or pasta for nutrient-dense complex carbs, such as ancient grains. Check out this article where I highlight some excellent grain options that are high in fiber and protein—plus, they're drought-resistant, making them a win for both your health and the environment! Pair these grains with legumes or animal based protein sources (chicken, red meat, fish) for a protein and fiber rich meal.
Sources:
F Guillon, M Champ, Structural and physical properties of dietary fibres, and consequences of processing on human physiology, Food Research International, Volume 33, Issues 3–4, 2000,
Pages 233-245, ISSN 0963-9969, https://doi.org/10.1016/S0963-9969(00)00038-7.
Glynn, E. L., Fleming, S. A., Edwards, C. G., Wilson, M. J., Evans, M., & Leidy, H. J. (2022). Consuming a Protein and Fiber-Based Supplement Preload Promotes Weight Loss and Alters Metabolic Markers in Overweight Adults in a 12-Week, Randomized, Double-Blind, Placebo-Controlled Trial. The Journal of nutrition, 152 (6), 1415–1425. https://doi.org/10.1093/jn/nxac038
Holt SH, Miller JC, Petocz P, Farmakalidis E. A satiety index of common foods. Eur J Clin Nutr 1995;49:675-90.
Ali Kohanmoo, Shiva Faghih, Masoumeh Akhlaghi, Effect of short- and long-term protein consumption on appetite and appetite-regulating gastrointestinal hormones, a systematic review and meta-analysis of randomized controlled trials, Physiology & Behavior, Volume 226, 2020,
113123, ISSN 0031-9384, https://doi.org/10.1016/j.physbeh.2020.113123.
Drummen M, Tischmann L, Gatta-Cherifi B, Adam T, WesterterpPlantenga M. Dietary protein and energy balance in relation to obesity and co-morbidities. Front Endocrinol (Lausanne) 2018;9:443. doi: 10.3389/fendo.2018.00443
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