Protein is an essential nutrient that plays a crucial role in the body with its most important function being building and repairing muscles. But just how much of this essential nutrient do you really need? I’m going to delve into protein requirements for men and women, including how they change over different life stages.
46 Grams of Protein Per Day is Not Enough
Traditionally, the minimum protein intake taught in medical schools based on CDC recommendations has been around a minimum of 46 grams per day. However, this amount is insufficient, in my opinion, and sets you up for a condition called sarcopenia, characterized by a decline in muscle mass and function. As we age, keeping an eye on our lean body mass becomes crucial for overall health and longevity. Aiming to maintain or increase lean body mass can positively impact healthspan. Protein plays a significant role in that.
I am currently recommending a minimum of 0.75 to 1 gram of protein per pound of lean body weight. Different life stressors can impact our protein needs. For instance, during pregnancy, the minimum protein requirement from the Institute of Medicine increases to 75 grams per day, as the developing baby relies on essential nutrients for growth. Once again, I think that intake should be higher in pregnant women. Athletes might need 0.55 to 0.9 grams per pound of body weight to support their active lifestyles and to maintain or increase muscle mass.
I consider my recommendations to represent a moderate intake. It’s important to point out that excess protein gets converted into sugar in the body (via a process called gluconeogenesis), driving up your insulin, driving down your testosterone, and potentially making you store more fat.
What does moderate protein look like? It means 3 to 4 ounces of wild-caught fish. Two eggs, a few times per week. One ounce of nuts or seeds. For instance, a woman weighing 130 pounds, with 100 pounds of lean body mass, should eat about 85 to 100 grams of protein each day, or enough to preserve lean body mass.
Protein Increases IGF-1 and Testosterone
One of the ways that protein helps preserve lean body mass and build muscle is by raising IGF-1 levels. IGF-1, or insulin-like growth factor 1, is a proxy for growth hormone that can be measured in the blood. Growth hormone is a build-you-up hormone, meaning that it plays a key role in building muscle and keeping bones strong, while simultaneously breaking down fat. It’s central to weight loss, and problems with growth hormone may be less recognized in women, compared to men. I discuss growth hormone at length in my latest book WOMEN, FOOD, AND HORMONES
You can raise IGF-1 by eating protein, particularly proteins rich in the amino acid called methionine. The goal is balance; you want to get the right amount of protein for you — not too much and not too little. However, many of the studies on protein consumption are limited to men. According to one, for men of ages forty to seventy-five, both animal and vegetable proteins raise IGF-11; in a smaller study of men, only red meat increased it.2 In women, higher protein intake has been associated with higher levels of IGF-1, but the association was limited to animal protein and did not apply to vegetable protein. Other research in athletes shows that whey protein shakes are particularly helpful at raising IGF-1 and testosterone, boosting IGF-1 in postmenopausal women, and increasing muscle mass in older folks.
Not All Protein is Created Equal
Eating a factory-farmed beefsteak and its constituent inflammatory hormones, antibiotics, xenoestrogens, arachidonic acids, and omega-6 fats sends a fire-alarm message of inflammation to your hormones. Eating a grass-fed bison steak, with its clean protein and omega-3 fats, fuels your body and your hormones in a healthy way. In my opinion, the two types of meat shouldn’t even be considered part of the same food group.
It is especially important to choose organic protein whenever possible because toxins that are rampant in conventionally raised meat confuse hormonal signaling, getting in the way of the clear message you’re trying to send to your hormones as you make efforts to maintain a lean body mass.
Good protein choices include the following items (in order of preference, starting with plants):
- Nuts (macadamia nuts, walnuts)
- Seeds (pumpkin, flax, hemp).
- Eggs (from cage-free chickens)
- Wild-caught fish (varieties that are low in heavy metals, such as salmon, mackerel, sardines, trout).
- Shellfish (crab, mussels, oysters, scallops, shrimp).
- Free-range poultry (higher in omega-3 fats), preferably dark meat, with skin on.
- Organ meats (from free-range, grass-fed sources).
- Grass-fed beef and wild game (maximum of twice per week), including beef jerky with no added sugar.
- Pork (free of antibiotics and hormones, at a maximum of twice per week — avoid if weight increases) — choose pork chops, pork ribs, and pork rinds (I add chopped pork rinds to my salads as an alternative to croutons).
You can also have a whey protein shake if you are having problems reaching the recommended daily intake, particularly if you are increasing the amount of strength training you are doing or more intense HIIT workouts.
Your Body Needs Carbs, Too
When engaging in intense exercise, combining protein with about 20 to 25 grams of carbs within 30 minutes after the workout can be highly beneficial. This combination aids in driving protein inside cells, promoting muscle recovery and function. So, next time you hit the gym or do strength training, consider consuming a functional shake as a great way to break a fast with dense nutrients, sufficient protein, and a small amount of carbs to restore the body.
Protein requirements for men and women change over the course of their lives, and individual factors play a role in determining the optimal intake. It’s important to take a personalized approach to your intake. Tracking lean body mass and making informed choices about protein sources can set you on the right path to a long and healthy lifespan.
M. Holmes et al., “Dietary Correlates of Plasma Insulin-like Growth Factor I and Insulin-like Growth Factor Binding Protein 3 Concentrations,” Cancer Epidemiology, Biomarkers, & Prevention 11, no. 9 (2002): 852–61.
S. M. Phillips et al., “Dietary Protein for Athletes: From Requirements to Optimum Adaptation,” Journal of Sports Sciences 29, Suppl. 1 (2011): S29–38; M. Huecker et al., “Protein Supplementation in Sport: Source, Timing, and Intended Benefits,” Current Nutrition Reports 8, no. 4 (2019): 382–396.
K. Zhu et al., “The Effects of a Two-Year Randomized, Controlled Trial of Whey Protein Supplementation on Bone Structure, IGF-1, and Urinary Calcium Excretion in Older Postmenopausal Women,” Journal of Bone and Mineral Research 26, no. 9 (2011): 2298–306.
J. M. Bauer et al., “Effects of a Vitamin D and Leucine-Enriched Whey Protein Nutritional Supplement on Measures of Sarcopenia in Older Adults, The PROVIDE Study: A Randomized, Double-Blind, Placebo-Controlled Trial,” Journal of the American Medical Directors Association 16, no. 9 (2015): 740–47; M. Rondanelli et al., “Whey Protein, Amino Acids, and Vitamin D Supplementation with Physical Activity Increases Fat-Free Mass and Strength, Functionality, and Quality of Life and Decreases Inflammation in Sarcopenic Elderly,” The American Journal of Clinical Nutrition 103, no. 3 (2016): 830–40; S. Verlaan et al., “Sufficient Levels of 25-Hydroxyvitamin D and Protein Intake Required to Increase Muscle Mass in Sarcopenic Older Adults — The PROVIDE Study,” Clinical Nutrition 37, no. 2 (2018): 551–57