All About the 30:30:3 Rule

A new diet – or rather, a framework for healthy eating – has taken the internet by storm since Dr. Amy Shah posted a video of herself explaining the concept on Instagram last July. Dr. Shah says that what’s obvious to her is that individuals should be aiming for 30 g of protein at their first meal, 30 g of fiber throughout the day, and three probiotic-rich foods every day.
According to Dr. Shah, this is an effective way to improve gut health and maintain a healthy balance of gut bacteria, curb cravings, balance blood sugar, promote satiety, support digestion, and boost the immune system. And apart from these three guidelines, individuals can continue their normal diets without heavy restrictions.
Seems relatively straightforward, right? But what does the science say?
Protein: Protein is one of the essential macronutrients we need each day. The recommended daily allowance (RDA) for protein is 0.8 g/kg of body weight per day, although most healthy individuals generally require much more than this, with recommendations for athletes and active individuals ranging anywhere from 1.2-2.0 g/kg/day, which is the equivalent of 82-136 g of protein daily for a 150-pound (68 kg) person.
Protein keeps us feeling full and satiated longer than eating, say, just carbohydrates. This is because protein takes longer to digest within our GI tract; the body must work harder to break down the complex structures of proteins into amino acids, whereas carbohydrates can be digested fairly quickly. Protein is also not stored in the body for later; it is either used immediately for building and repairing muscle tissue, converted to energy if needed (i.e., if there are not enough carbohydrates available), or excreted in urine.1
Adequate protein intake also helps to maintain muscle mass and strength, a crucial part of healthy aging. Depending on your goals, increased protein intake can also help you build muscle mass.
Fiber: Similar to protein, fiber also has the power to digest slowly, leaving us feeling fuller for a longer period of time. In fact, it passes through our digestive tract largely undigested. Instead of getting digested and being used for nutrients, bacteria in the large intestine ferment the fiber, which produces health-promoting byproducts like short-chain fatty acids (SCFAs), which can benefit immunity and metabolism, as well as protect the mucus membranes in the GI tract.2
Additional benefits of fiber include supporting healthy blood sugar levels by slowing its absorption into the bloodstream, reducing cholesterol by decreasing its absorption and enhancing elimination, trapping toxic substances and eliminating them from the body, decreasing transit time, increasing fecal bulk, and providing numerous gut health benefits. In fact, fiber is also known as a prebiotic, or food for probiotics.3
Although we already know fiber is good for us, most people living in the U.S. are falling short of the recommended daily amounts of fiber. According to the FDA, it is recommended for women to consume 25 g of fiber per day, and men to consume 38 g of fiber per day. So, the recommendation of 30 g of fiber throughout an entire day, based on the 30:30:3 method, isn’t too far off base.
Probiotics: Probiotics are live, active bacteria and yeasts (fed by prebiotics) found in certain foods, including yogurt, kefir, kombucha, kimchi, sauerkraut, and tempeh, as well as supplements. When probiotics are consumed or supplemented in adequate amounts, they can provide benefits to the person taking them.
While it is not guaranteed, and depends on the specific strain, probiotics may positively change the balance of microbes in the GI tract (maintaining and creating the “good” bacteria) while suppressing the growth of pathogenic bacteria (the “bad” bacteria). Probiotics can also help with occasional digestive upset, support healthy immune function, and aid in weight management efforts.*
While there are no daily recommendations for probiotic-rich foods, it is recommended to add more of them to your diet. Aiming for three servings per day, or one at each meal, is a great place to start.
Meal and snack examples using the 30:30:3 framework
Breakfast
- 1 cup of plain Greek yogurt
- 2 tablespoons almonds
- 1 tablespoon chia seeds
- ½ cup raspberries
- ⅓ cup granola
Totals = 30 g protein, 12 g fiber, 1 probiotic-rich food
Lunch
- 1 lavash wrap
- 3-4 oz shredded chicken or tuna
- 1 oz cheese
- ½ avocado
- 1 handful of baby carrots
Totals = 37-45 g protein, 8 g fiber
Snack
- 8 oz kefir
Totals = 11 g protein, 1 probiotic-rich food
Dinner
- 1 cup rice
- 4-5 oz salmon (or other fatty fish)
- 1 cup cooked broccoli
- ½ avocado
- 2 tablespoons sauerkraut or kimchi
Totals = 29-34 g protein, 11-13 g fiber, 1 probiotic-rich food
The takeaway
While it might be considered one of the new trendy ways of eating, there is some merit to the 30:30:3 framework. Including more protein, fiber, and probiotic-rich foods in your diet can add numerous health benefits to your gut and musculoskeletal system, to name a few.
For more nutritional guidance, check out Thorne’s Wellness Guides, free informational packets on various health and wellness topics, put together by Thorne’s Medical Affairs team.
References:
- Lonnie M, Hooker E, Brunstrom JM, et al. Protein for Life: Review of Optimal Protein Intake, Sustainable Dietary Sources and the Effect on Appetite in Ageing Adults. Nutrients. 2018;10(3):360. Published 2018 Mar 16. doi:10.3390/nu10030360
- Dhingra D, Michael M, Rajput H, Patil R. Dietary fibre in foods: a review. J Food Sci Technol 2012 Jun;49(3):255-266.
- Makki K, Deehan E, Walter J, Bäckhed F. The impact of dietary fiber on gut microbiota in host health and disease. Cell Host Microbe 2018;23(6):705-715.