The Protein Gap: Why Most Plant-Based Adults Over 40 Aren’t Getting Enough

Clean eating. Whole foods. Mostly plants. For many adults over 40, that’s the foundation of wellness.

Yet even the most intentional diets can fall short. Leading nutrition experts now highlight one recurring deficiency: protein.

Research demonstrates that conventional protein guidelines do not meet the needs of adults in midlife, especially those eating plant-based diets. This conversation is not about diet trends—it’s about resilience, recovery, and truly thriving as we age.

Protein: The Biochemical Essential

Protein is fundamental to nearly every aspect of health—it fuels the production of enzymes, hormones, and neurotransmitters, supports tissue repair, maintains mitochondrial function, and preserves the integrity of the gut lining. It also plays a critical role in regulating immune responses, appetite, and blood glucose levels. As we age, our efficiency in using protein declines—a condition known as anabolic resistance—making consistent, high-quality protein intake increasingly vital .

Updated Guidelines for Midlife Adults

The standard RDA of 0.8 g/kg per day was designed to prevent deficiency—not to promote long-term health, strength, or metabolic function. But experts like Dr. Donald Layman, professor emeritus at the University of Illinois and one of the most cited researchers in protein metabolism, argue that this decades-old benchmark is no longer sufficient. On The Dr. Gabrielle Lyon Show, Layman explained that the RDA was developed from nitrogen balance studies that ignore how protein is distributed across meals, how it supports daily metabolic repair, and how protein quality affects bioavailability.

Instead, Layman recommends 30 grams of high-quality protein per meal, based on the amount needed to trigger muscle protein synthesis—particularly the activation of the amino acid leucine. He and Lyon emphasize that meal-by-meal protein distribution is more impactful than simply hitting a daily total, especially for adults 40 and over who are managing work stress, hormonal changes, and shifts in metabolism. Their view: a protein-forward breakfast and lunch may improve energy, body composition, and long-term resilience better than protein loading at dinner alone.

A 2022 systematic review and meta-analysis published in the Journal of Cachexia, Sarcopenia and Muscle found that protein intake of 1.2 to 1.6 g/kg/day significantly supports improvements in muscle mass and lower-body strength in healthy adults under and over 65, particularly when paired with resistance exercise.

Even mainstream outlets like The Guardian now recommend higher protein targets for midlife and older adults. A feature by Fleming (2024) titled “The truth about protein: how to get enough – at every age” highlights that while official guidelines often point to around 0.8 g/kg, experts are increasingly recommending 1.0 g/kg or more—especially during menopause and beyond—to support energy, muscle mass, and metabolic health in aging populations.

These differences—1.0 g/kg from public-facing UK sources like The Guardian, 1.2–1.6 g/kg in American scientific journals, and 30 grams per meal from metabolism researchers like Dr. Layman—reflect a growing consensus that the RDA is outdated. Though individual numbers may vary, the trajectory is clear: future guidelines will likely raise protein targets across all age groups, especially for aging adults, plant-based eaters, and women in midlife.

Plant-Based Protein—It’s Achievable With Strategy

While plant-based diets offer many health advantages, they require intentional design to meet elevated protein needs. Staples like vegetables, grains, and oils have low protein density unless paired strategically with legumes, seeds, or supplements.

Rich and accessible plant-based protein sources include:

• Lentils, moong dal, chickpeas—rich in lysine and fiber

• Tofu, tempeh, edamame—complete protein alternatives

• Quinoa, teff, amaranth—ancient grains with high amino profiles

• Hemp, chia, flax, pumpkin seeds—high in protein and micronutrients

• Nuts and nut butters—moderate protein with healthy fats

A 2025 systematic review published in The Journal of Nutrition examined protein adequacy and sources across various plant-forward diets. It found that vegans had the highest proportion of plant protein intake—ranging from 77% to 98%—with legumes, peas, and lentils contributing significantly to overall protein. Compared to semivegetarians, vegans were more likely to meet recommended intake levels due to their emphasis on protein-rich plant foods (Rolands et al., 2025).

Dr. Rupy Aujla, a UK-based physician and nutritional medicine expert, emphasizes the role of high-protein, plant-forward eating in promoting strength, energy, and resilience beyond age 40. In his cookbook Healthy High Protein (Aujla, 2025), he outlines how combining legumes, seeds, tofu, and protein-rich grains can help support cognitive function, hormonal balance, and metabolic health—without relying on animal products or ultra-processed substitutes.

Timing Matters—Protein at Breakfast

It’s not just how much protein you consume—but when you consume it. A recent review in Nutrition Reviews found that adults who consumed a greater proportion of their daily protein at breakfast were more likely to maintain muscle mass and, in several studies, demonstrated stronger grip strength compared to those who consumed most of their protein later in the day.

Supporting this, a 2024 mini review in Frontiers in Nutrition emphasized the benefits of “chrononutritionally aligned” eating patterns, noting that the body is more responsive to amino acid uptake and muscle protein synthesis in the morning—especially following an overnight fast.

Midlife Metabolism: Why Protein Matters More Now

From the age of 30 onward, skeletal muscle mass begins to decline by about 1% per year—a gradual shift that affects metabolism, immune function, and even cognitive health (Janssen et al., 2000). Left unaddressed, this age-related muscle loss accelerates over time, contributing to fatigue, frailty, and reduced resilience to stress or illness.

A 2022 population-based study from Korea found that adults consuming less than 1.0 g/kg/day of protein were up to 4.3 times more likely to have low muscle mass compared to those meeting or exceeding that threshold (Huh & Son, 2022). This held true not just for older adults, but across all age groups—highlighting the importance of prioritizing adequate protein intake starting in midlife, before functional decline sets in.

Making It Practical: What 25–30 Grams of Protein Looks Like

✔️ Smoothie w/ Hemp & Greens: Pea protein (20 g), hemp seeds (5 g), almond milk, spinach, chia (2 g) = ~27 g

✔️ Lentil & Quinoa Bowl: Lentils (18 g), quinoa (6 g), tahini, seeds = ~28 g

✔️ Tofu Scramble: Tofu (20 g), hemp seeds (5 g), greens = ~29 g

✔️ Chia Pudding: Chia (6 g), soy milk (7 g), almond butter, protein = ~26–28 g

✔️ Moong Dal & Millet: Dal (14 g), millet (5 g), flax/hemp = ~27–28 g

✔️ Misir Wot with Injera: Lentil stew (18 g), injera (10 g), greens = ~30 g

✔️ Black Bean & Amaranth: Beans (15 g), amaranth (4 g), veggies + seeds = ~25–26 g

✔️ Khichdi + Raita: Moong dal (14 g), millet (5 g), yogurt (4 g), seeds = ~26–28 g

✔️ Mujadara + Tahini: Brown lentils (13 g), rice (4 g), tahini, salad = ~25 g

✔️ Chickpea Fatteh: Chickpeas (15 g), pita (4 g), yogurt (4 g), nuts = ~27–28 g

✔️Adai Dosa + Chutney: Dosa (13–15 g), peanut chutney = ~25–27 g

In summary - Protein intake in your 40s and beyond should be viewed as a form of resilience—it supports cognition, immune function, hormone health, and metabolic balance. By adopting a plant-heavy, protein-forward, and morning-focused eating strategy, you align with compelling scientific findings—and with how your body truly needs to be fed as it ages.

References

Aujla, R. (2025). Healthy High Protein. Ebury Press.

Bauer, J., et al. (2013). Evidence-based recommendations for optimal dietary protein intake in older people. Journal of the American Medical Directors Association, 14(8), 542–559. https://doi.org/10.1016/j.jamda.2013.05.021

Deutz, N. E., et al. (2014). Protein intake and exercise for optimal muscle function with aging: Recommendations from the ESPEN Expert Group. Clinical Nutrition, 33(6), 929–936. https://doi.org/10.1016/j.clnu.2014.04.007

Fleming, N. (2024, April 15). The truth about protein: how to get enough – at every age. The Guardian. https://www.theguardian.com/lifeandstyle/2024/apr/15/truth-about-protein-how-to-get-enough-every-age

Groenendijk, M., et al. (2024). Chrononutrition: A mini-review. Frontiers in Nutrition, 11, 1305729. https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2024.1394916/full

Janssen, I., et al. (2000). Skeletal muscle mass and distribution in 468 men and women aged 18–88 yr. Journal of Applied Physiology, 89(1), 81–88. https://doi.org/10.1152/jappl.2000.89.1.81

Khaing, I. K., Tahara, Y., Chimed-Ochir, O., Shibata, S., & Kubo, T. (2025). Effect of breakfast protein intake on muscle mass and strength in adults: A scoping review. Nutrition Reviews, 83(1), 175–199. https://pubmed.ncbi.nlm.nih.gov/38219154/

Lyon, G. (Host). (2024, November 19). Why nutrition guidelines need a major overhaul (Dr. Donald

Layman) [Audio podcast episode]. In The Dr. Gabrielle Lyon Show. https://drgabriellelyon.com/podcast_list/why-nutrition-guidelines-need-a-major-overhaul-dr-donald-layman/

Nunes, E. A., Colenso‑Semple, L., McKellar, S. R., Yau, T., Ali, M. U., Fitzpatrick‑Lewis, D., Sherifali, D., Gaudichon, C., Tomé, D., Atherton, P. J., Robles, M. C., Naranjo‑Moncada, S., Braun, M., Landi, F., & Phillips, S. M. (2022). Systematic review and meta‑analysis of protein intake to support muscle mass and function in healthy adults. Journal of Cachexia, Sarcopenia and Muscle, 13(2), 795–810. https://doi.org/10.1002/jcsm.12922

Rolands, M. R., Hackl, L. S., Bochud, M., & Lê, K. A. (2025). Protein adequacy, plant protein proportion, and main plant protein sources consumed across vegan, vegetarian, pescovegetarian, and semivegetarian diets: A systematic review. The Journal of Nutrition, 155(1), 153–167. https://www.sciencedirect.com/science/article/pii/S0022316624004504?via%3Dihub

Huh, Y., & Son, K. Y. (2022). Association between total protein intake and low muscle mass in Korean adults: Analysis from the Korea National Health and Nutrition Examination Surveys (KNHANES) 2008–2011. BMC Geriatrics, 22, 319. https://doi.org/10.1186/s12877-022-03019-1