DIETARY FIBER & PROTEIN 101

DIETARY FIBER’S ROLES IN THE BODY

One of the primary roles of fiber in the body includes capturing metabolic waste products and acting as an intestinal bulking agent to aid in more complete elimination of waste materials (we’re talking bowel movements here people). But dietary fiber (including prebiotic fibers like acacia and functional fibers like psyllium) has many benefits besides improving regularity. Adequate fiber intake has been linked to several important health markers, including improved digestive health and a reduced risk of several conditions, including constipation, heart/cardiovascular disease, type 2 diabetes, colon cancer, hyperlipidemia, arthritis and obesity.


DAILY RECOMMENDATIONS

The USDA’s recommendations for fiber for adults is 25-38g a day. I generally advise my clients to aim for 25-50g a day. While there is no set Tolerable Upper Intake Level (UL) for fiber, consuming too much fiber (usually 50-70g/day or more) can cause gastrointestinal upset, pain, gas, cramping, bloating and even nutrient deficiencies.


In looking at the studies and statistical data on fiber consumption, most Americans aren’t suffering from consuming too much fiber but rather too little. On average, American adults consume 12-18g of fiber each day, which is roughly half of the recommended amount. Insufficient fiber intake can lead to sluggish digestion, impacted intestinal fecal matter, fatty stools, incomplete elimination of waste materials, constipation and an increased risk of developing diverticulitis (and other kinds of inflammatory intestinal diseases). [1-4]



SOME OF MY FAVORITE SOURCES OF DIETARY FIBER

Some of my favorite sources of fiber from foods include…

· Low calorie veggies-> broccoli, Brussels sprouts

· High fat items-> avocados, almonds

· High simple carb items-> certain berries, pears, apples

· High complex carb items-> winter squash, green peas, oatmeal, beans

· High “combo” items-> almond flour, ground flax, chia seeds [5]



SOME OF MY FAVORITE FIBER SUPPLEMENTS

Some of my favorite fiber supplements include…

· Psyllium

· Wheat dextrin (classed as gluten free <20ppm, ex. Benefiber)

· Acacia (ex. Heather’s acacia fiber)

· Pectin (most often derived from apples)

· XOS/xylo-oligosaccharide (ex. Life Extension Florassist Prebiotic)



There are other fiber supplements that I generally don’t recommend as often as those listed above. These include…

· Inulin/FOS (sourced from Jerusalem artichoke/Sunchoke, chicory root or agave)

· Guar gum

· GOS/galacto-oligosaccharide

· Methycellulose (chemically treated wood pulp)

· Polydextrose (synthetic polymer of glucose)



FIBER SUMMARY

In short, fiber is an important dietary nutrient (or some might say “non-nutrient”) and is used by the body to help capture metabolic waste products and as a bulking agent to aid in more complete elimination of waste materials. Most adults would likely benefit from regularly consuming 25-50g of non-inflammatory fiber a day.


Some good food-bound forms of fiber include broccoli, Brussels sprouts, avocado, almonds, some berries, pears, apples, beans, green peas, oats, winter squash, blanched almond flour, ground flaxseed and chia seed (those wishing to reduce carb intake for weight loss purposes may want to avoid some or all of the high-carb fiber options).


Some good supplemental sources of fiber include psyllium, wheat dextrin, acacia, pectin and XOS/xylo-oligosaccharide.


THE 20 PROTEIN-BUILDING AMINO ACIDS

Amino acids are made up of oxygen, carbon, hydrogen, nitrogen. And while some 500 naturally-occurring amino acids have been identified thus far, for humans only 20 of these have been identified as being protein-building amino acids. These 20 are sometimes categorized as follows…


Essential: 9 amino acids are considered essential, meaning the body can’t produce them on its own and needs to obtain them from dietary sources


Conditionally-Essential: 6 aminos are considered either conditionally-essential, meaning that the body, under certain circumstances, isn’t able to produce these amino acids on its own and needs them from dietary sources

Non-Essential: 5 aminos are considered non-essential, meaning the body, under all observed circumstances, can produce these amino acids on its own). [6-7]



DIETARY PROTEIN’S ROLES IN THE BODY

Dietary protein is essential for all metabolic functioning and plays a major role in…

· cell and tissue building and repair (including muscle building and repair)

· proper immune system functioning and

· the production of enzymes.


As for using protein as a general fuel source (for “energy”), dietary protein is normally a tertiary (third tier) fuel source, behind fat (normally a secondary source of energy) and carbs (normally a primary source of energy).



DAILY RECOMMENDATIONS

Be warned- this part can get confusing, but I’ll do my best to make it as simple as I know how (thanks to scientific error and our government, the question of “How much protein should I consume?” is more complex than it needs to be).


BASING PROTEIN INTAKE OFF GOVT. GUIDELINES

On one hand we have the Dietary Reference Intakes, which for protein are relatively strait forward. For adult men and women (18+ years old), the government’s recommendation is 46-71 grams a day. The ranges for nutrients here are given using a 5’10”, 154lbs man and a 5’4”, 126lbs woman as the default “reference man” and “reference woman” (note that the average U.S. adult man is 200lbs and the average adult woman is 170lbs). While I think 46-71g of protein a day is too low for many adults, I like that the recommendation is given in grams/day (instead of as a percentage of caloric intake).


HOWEVER, the U.S. government doesn’t stop here. There are ALSO the Dietary Guidelines, which give guidelines for calories along with recommended percentages of proteins, fats and carbs… and this is where it can get really confusing (at least for a simpleton like me). For men 18 years of age and older, the recommended calorie range is 2000-3200 cals/day. For women it’s 1600-2400 cals/day. For protein, the recommendation is 10-35% of daily calories from protein. So now we have to do some math to convert these numbers into grams per day. For men, on the low end we’re looking at 10% of 2000 cals, which equals 200 cals from protein. Then we divide this by 4 (remember, 4 cals per gram for protein) to arrive at 50, which is to say 50 grams of protein per day. Get it? Instead of doing that again, I’ll just list the ranges we arrive at below…


Protein guidelines, for men: 50g to 280g a day

Protein guidelines, for women: 40g to 210g a day


And here is where we see our dilemma: a recommendation of 46-71g a day stands in stark contrast to one of 40-280g a day.


So that’s the government’s word on it. [8-11]


BASING PROTEIN INTAKE OFF CURRENT WEIGHT

But what do other experts and researchers say? As with almost everything there is, of course, disagreement and conflicting stances, but a common recommended range is 0.6-1.2g of protein per pound of body weight, per day. [12-14]


BASING PROTEIN INTAKE OFF LEAN MASS

There are other researchers who recommend protein intake based off lean mass instead of overall bodyweight (ex. Volek and Phinney’s The Art and Science of Low Carbohydrate Performance, published in 2012). [15]


I believe it’s more appropriate to prescribe macronutrient recommendations based off of lean mass rather than total body weight, as the goal is to supply the body’s metabolically active tissues (and not adipose tissue/body fat) with nutrients like protein. Additionally, women tend to have a higher bodyfat percentage than men (generally around 10% higher), which means a 200lb woman might have 20 more pounds of bodyfat than a 200lb man. Giving the same daily protein intake goal to these two people might not be immediately harmful, but it would hardly be ideal.


BASING PROTEIN INTAKE OFF IDEAL BODY WEIGHT

Part of my goal here is to make calculating daily macronutrient goals as simple for people as possible (without overly simplifying it of course). In that I often set daily macronutrient goals (particularly with protein and fat) based off ideal or goal weight. For example, a female client in her late 30s came to me last year saying she wanted to lose 90lbs (from 230lbs to 140lbs). Based on her height, frame size and body shape I agreed that her target weight could be a healthy weight for her. For her protein intake we used 0.8-1.0g/day based on her ideal weight. In other words, 110-140g dietary protein a day. She was highly compliant in the personalized program we put together for her, and she ended up losing 85lbs in 9 months!


For this approach, I’ve listed some target daily protein intake goals based off of ideal body weights below…



Several factors can affect the above recommendations. For examples, for individuals with healthy digestive systems (indicating they can break down and absorb higher amounts of proteins) who are engaging in relatively high amounts of exercise (particularly strength training), a higher protein intake may be preferred.


Conversely, for individuals who struggle to properly break down and absorb foods (including high protein foods), a lower daily protein intake goal may be more appropriate. Additionally, intermittent fasting has been proven to be a powerful therapeutic tool for many health conditions, and those engaging in time restricted eating or complete fasting (ex. 24 hours of no caloric intake) will obviously not fall into the above 0.8-1.0g protein per pound of ideal body weight, per day range.


“COMPLETE” & “INCOMPLETE” PROTEINS

Proteins from clean animal sources (including eggs, wild-caught fish, poultry, red meat and dairy, along with whey and egg protein powders) are generally considered “complete”, meaning that they contain a more robust amino acid profile than proteins from singular plant sources. Proteins from plant sources (including grains, beans, nuts, seeds and vegan protein powders) are generally considered “incomplete”, meaning that they contain a less robust amino acid profile than proteins from singular animal sources. However, plant proteins can be made “complete” by combing certain plant proteins. [16-19]



PROTEIN SUMMARY

In short, proper digestion and absorption of adequate amounts of high-quality dietary protein is crucial to maintaining overall health, and is especially important in regards to 1) maintaining (or building) muscle mass, 2) optimizing immune functioning, 3) proper endocrine and hormonal functioning, and 4) enzymatic production and functioning in the body.


A regular daily protein intake of 0.8-1.0 grams of protein per pound of ideal body weight is likely well-suited for the needs of most adults. A diet that contains adequate amounts of high-quality animal-based proteins (ex. wild-caught fish, organic eggs, organic poultry, grass-fed red meat, and certain kinds of high-quality dairy, such as grass fed whey protein supplements), and high-quality plant-based proteins (from gluten-free grains, beans, nuts, seeds and vegan protein powders) can help to ensure that the body will have access to adequate amounts of all of the amino acids necessary for optimal physical functioning.


A weight loss approach with insufficient amounts of protein may result in a loss of muscle mass along with a loss of body fat. For many adults, losing muscle mass can have negative metabolic effects, which can work to predispose a dieter to an increased risk of re-gaining some (or all) of the lost weight back.


SOURCES

1 https://nutritionfacts.org/2015/09/29/where-do-you-get-your-fiber/

2 www.drcarney.com/blog/entry/97-of-people-are-deficient-in-this-nutrient

3 www.cnpp.usda.gov/sites/default/files/nutrition_insights_uploads/Insight36.pdf

4 https://ketogenic.com/nutrition/fiber-whats-scoop/

5 www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/high-fiber-foods/art-20050948

6 www.ncbi.nlm.nih.gov/pmc/articles/PMC4634941/

7 www.aminoacid-studies.com/amino-acids/what-types-of-amino-acids-are-there.html

8 https://health.gov/our-work/nutrition-physical-activity/dietary-guidelines/previous-dietary-guidelines/2015

9 www.nationalacademies.org/hmd/~/media/Files/Activity%20Files/Nutrition/DRI-Tables/8_Macronutrient%20Summary.pdf?la=en

10 www.cnpp.usda.gov/sites/default/files/usda_food_patterns/EstimatedCalorieNeedsPerDayTable.pdf

11 www.nationalacademies.org/hmd/Reports/2002/Dietary-Reference-Intakes-for-Energy-Carbohydrate-Fiber-Fat-Fatty-Acids-Cholesterol-Protein-and-Amino-Acids.aspx

12 www.bodybuilding.com/fun/maki1.htm

13 https://bayesianbodybuilding.com/the-myth-of-1glb-optimal-protein-intake-for-bodybuilders/

14 www.muscleforlife.com/how-much-protein-build-muscle/

15 https://ketodietapp.com/Blog/page/KetoDiet-Buddy

16 www.healthline.com/nutrition/animal-vs-plant-protein#section7

17 www.verywellfit.com/vegan-protein-combinations-2506396

18 www.builtlean.com/2012/10/03/complete-vs-incomplete-protein-sources/

19 www.sciencestrength.com/sciencestrength/2015/12/07/the-complete-incomplete-protein-story