Many people insist weight control is as simple as "calories in, calories out." Health, on the other hand, isn't nearly so simple. For optimal health and athletic performance, fill your belly with foods that pack not only calories from macronutrients, but also adequate amounts of certain must-have micronutrients.
Vitamin C and vitamin B-1 (thiamin) are two crucial water-soluble vitamins that provide an abundance of benefits. The immune-boosting properties of vitamin C can help you continue hitting the weights hard throughout the ebb and flow of volume and intensity, while B-1 will ensure you have the energy needed to complete those high-volume sessions.
Vitamin C: Why You Need It, And How Much You Need
Vitamin C plays an important role in immune function and is essential for proper functioning of immunity-boosting cells like T-cells.  Additionally, vitamin C acts as an antioxidant to rid the body of those nasty, stress-induced free radicals.
Vitamin C may also help support the health of tendons and ligaments. That's because this benevolent water-soluble vitamin is used to make collagen. The most abundant protein in the body, collagen functions in the growth and repair of bodily tissues such as tendons, ligaments, skin, blood vessels, and bone. 
Collagen also aids in the absorption of the type of iron found in plant-based foods by converting it to a more absorbable form. This is especially important for female athletes to know, as women are more likely to be iron-deficient than men. Besides causing you to feel fatigued, iron deficiency can lead to frequent infections, headaches, cold hands and feet, and overall weakness.
How much you need: The current RDA for vitamin C is set at 60 milligrams per day for both men and women. However, research strongly suggests an intake of 90-100 milligrams per day to reduce the risk of cardiovascular disease and cancer. 
Foods Rich In Vitamin C
1. Kiwi: 117% RDA Per Kiwi
While oranges get all the accolades when it comes to vitamin C, gram for gram, this fuzzy fruit actually provides more. In fact, the kiwi might be good-mood food. In a study conducted in the Journal of Nutritional Science, investigators found that people who ate two kiwi every day for six weeks tended to have a more positive outlook on life.  The payload of vitamin C in kiwi may play a role in emotion-stabilizing brain functions.
2. Yellow Bell Pepper: 569% RDA Per Large Pepper
Dietitians often trumpet the importance of eating the rainbow to obtain a full arsenal of nutrients and antioxidants, so make sure to include yellow peppers in your salads and stir-fries for a significant shot of vitamin C. The supermarket stalwart also supplies some vitamin B-6, which plays a major role in serotonin production. Serotonin is essential for optimal mood balance. You can also load up on vitamin C with red bell peppers.
3. Broccoli Stalks: 177% RDA Per Stalk
As a surprisingly great source of vitamin C, broccoli stalks should be in your belly, not the compost bin. The fibrous outer layer covers deliciously tender stalks. You can shave them into ribbons with a vegetable peeler and add them raw to salads and slaws. You can slice them thinly and toss them into a skillet when making stir-fries or sautéing up a bunch of leafy greens. The florets are also jam-packed with vitamin C.
Other good sources of vitamin C include parsley, kale, mustard greens, hot peppers, peaches, strawberries, grapefruit, orange, pummelos, Brussels sprouts, and mangoes.
Thiamin Why You Need It, And How Much You Need
Also known as vitamin B-1, thiamin is a water-soluble vitamin required for your cells to be able to generate energy from carbohydrates. When you eat carbs from oats, sweet potato, or fruits, your body calls upon this nutrient to convert those carbs into useful energy to help power your workouts and other daily functions. Thiamin also plays a role in conducting nerve impulses and muscular contractions. 
How much you need: Men need to take in 1.2 milligrams daily, while women should consume 1.1 milligrams each day.
Foods Rich In Thiamin
1. Pork Tenderloin: 57% RDA Per 3 Ounces
More flavorful than chicken breast, pork tenderloin is an economical source of thiamin and protein—each 3-ounce serving has 18 grams of tender protein goodness. Ounce for ounce, it contains five times less fat than beef tenderloin with an easier-to-swallow price tag.
To prepare pork tenderloin, preheat your oven to 450 degrees F. Heat 1 tablespoon of oil in an ovenproof skillet over medium-high heat. Add the pork and sear it until it's browned on all sides, about 6-8 minutes. Transfer the skillet to the oven and roast the pork until an instant-read thermometer inserted into thickest part of the meat registers 145 degrees F, another 10-15 minutes. Let the tenderloin rest 10 minutes before slicing.
2. Lentils 56%: RDA Per 1/2 Cup
Sure, thiamin is one of the nutrients pumped back into refined grains, but a much healthier approach to getting what you need each and every day is to focus on whole-food sources like lentils. On top of energy-boosting thiamin, budget-friendly lentils supply plant-based protein and a wide berth of other must-have nutrients like folate, magnesium, and iron. Pair your lentils with a sauté of broccoli stalk greens for enhanced iron absorption!
3. Wheat Germ: 36% RDA Per 1/4 Cup
Unprocessed wheat consists of three parts: endosperm, germ, and bran. Refining strips away the fiber-rich bran and nutrient-dense germ, leaving behind the starchy, nutrient-poor endosperm. This makes concentrated wheat germ an often overlooked source for a range of useful nutrients like thiamin, phosphorus, vitamin B-6, and zinc. Whether in oatmeal, pancake batter, or a coating for chicken, wheat germ can easily find its way into your day.
Other good sources of thiamin include black beans, navy beans, rice bran, oat bran, oats, barley, kamut, flaxseed, tahini, ham, and venison.
- Ströhle, A., & Hahn, A. (2009). Vitamin C and immune function. Medizinische Monatsschrift fur Pharmazeuten, 32(2), 49-54.
- Boyera, N., Galey, I. & Bernard, B.A. (1998). Effect of vitamin C and its derivatives on collagen synthesis and cross-linking by normal human fibroblasts. International Journal of Cosmetic Science, 20(3). 151-158.
- Carr, A. C., & Frei, B. (1999). Toward a new recommended dietary allowance for vitamin C based on antioxidant and health effects in humans. The American Journal of Clinical Nutrition, 69(6), 1086-1107.
- Carra, A.C., Bozoneta, S.M., Pullara, J.M. & Vissera, M.C. (2013). Mood improvement in young adult males following supplementation with gold kiwifruit, a high-vitamin C food. Journal of Nutritional Science, 2, 24-32.
- Ehrlich, S. (2015). Thiamin. University of Maryland Medical Center. Accessed December 16, 2015. https://umm.edu/health/medical/altmed/supplement/vitamin-b1-thiamine.