Macronutrients or ‘macros’ have become a hot topic in the health and nutrition world, particularly for those looking to lose weight. But the truth is, if you're focused on getting the proper balance of each, it shouldn't be for weight loss, but rather for optimal body function. Here’s how you can use macros to optimize your biomarkers and reach your goals.
What are macronutrients?Macros are nutrients which are required by the body in large amounts (hence "macro"). In large part, this term refers to three main calorie sources: carbohydrates, fats, and protein (alcohol also provides calories, but by no means does your body need it to survive). We know that we need all of these macronutrients for growth and development, but getting a disproportionate amount of our calories from one and or another can negatively alter certain biomarkers.
Fats: Not all are created equallyFats have gone from feared—during the low-fat diet trend of the 90’s—to adored during today’s keto kick. The former generally led to replacing fats (including healthy ones) with refined carbohydrates, which we know isn't good for health. But the other end of the spectrum—a ketogenic diet—doesn’t appear to be the answer for long-term health either. To learn more about the potential dangers of the keto diet, read this blog.
Dietary fat is crucial, as it provides important fuel for the body while aiding in the absorption of fat-soluble vitamins (A, D, E, and K) and carotenoids (a type of antioxidant). Some dietary fats, like omega-3s, are also "essential," meaning our bodies can't produce them, so we have to get them from our diets.  Finding the balance between too little and too much is key and here are some ways you can work to achieve it.
First, the type of fats you eat can impact your lipid group; LDL cholesterol, HDL cholesterol, triglycerides, and total cholesterol levels.
Saturated and trans-fats (unhealthy):
- Found in animal based foods such as cheese, high-fat cuts of meat, whole-fat dairy products, and in plant-based palm and coconut oils.
- Also prevalent in processed foods, so be sure to check your food labels!
- Can negatively impact your heart health by raising LDL and lowering HDL cholesterol levels.
- Coconut oil, a plant-based saturated fat, has been lauded lately for being a health food, but there is insufficient research to suggest that this oil is healthier for our arteries than other saturated fats.
Polyunsaturated and monounsaturated fats (healthy):
- Monounsaturated fats are found in avocados, nuts, and olive oil.
- Polyunsaturated fats, more well-known as omega-6 and omega-3, can be found in foods such as safflower, soybean, and corn oil (omega-6) and flaxseed, walnuts, and fatty fish (omega-3).
- Help to keep cells pliable and resilient against damage
- Help improve inflammation-related markers such as cortisol, white blood cell count, and hsCRP down.
So how much fat should you have?
- Aim for a fat intake of ~20-35% of your total calories according to the Dietary Reference Intakes (DRIs). 
- Aim to get your healthy fats from naturally fatty whole foods, like the ones listed above.
- In very active individuals, getting adequate fat and calories is important for optimizing hormones and the hormone precursor DHEAS in women, total testosterone in men, and SHBG in both males and females.
Protein: Get enough, but more isn't always betterThis macronutrient is hyped as the most critical by many athletes and has really been in the limelight with the new wave of fitness coverage on social media. It’s necessary for muscle repair, growth, and recovery, as well as more medial bodily functions like making enzymes, hormones, and neurotransmitters.
Though, while it certainly deserves your attention, more protein doesn't always mean better. This article from Harvard sums up the risks of excessive protein intake. Regardless, your protein requirements will vary with a number of things including your age, sex, weight, activity levels, and your fitness goals:
- The protein DRI for the average individual is 0.8g/kg of body weight.
- This is moderately higher in very active individuals, with a range of 1.4-2.0g/kg of body weight. [2,3]
- Good sources of protein include both animal and plant based sources, including eggs, fish, beef, poultry, lentils, edamame, and tofu. Protein powders, such as whey protein, can also be included and may help improve cortisol levels.
So which biomarkers should you keep an eye on if you’re concerned about protein? Well, if you’re exercising on the regular, keep an eye on your creatine Kinase (CK), ALT, and AST as these will all provide a glimpse into your muscle health and recovery. These enzymes become elevated after strenuous exercise, and if they stay too high for too long, it may be a clue that you're not allowing for optimal recovery between workouts. In contrast, high levels of albumin can indicate that you are dehydrated or getting too much protein.
Carbohydrates: Quality over quantityFinally, this macro has become public enemy #, but it truly is just as important at the others in the big picture of health! Carbohydrates provide the body with its preferred source of fuel, glucose. The Dietary Guidelines for Americans recommend that carbohydrates make up 45-65% of your daily calories. 
Looking more closely, the timing, type, and amount of carbs you should be consuming will also vary based on your age, sex, weight, activity levels, and fitness goals:
- Aim to get your carbs from a variety of fruits, vegetables, legumes, and whole grains
- Limit processed grains and added sugars to less than 10g per day. Here's a blog that summarizes the differences in how ultra-processed foods act on our bodies compared to whole ones.
- If you’re an athlete or active individual, you will need to consume enough carbohydrates to fuel your lifestyle. This blog breaks down macro needs by activity level.
Paying attention to your glucose group (both fasting blood glucose and HbA1c) will help guide you in choosing your carbohydrate sources. Fasting blood glucose can be elevated for a number of reasons, including physical and emotional stress, so HbA1c helps to give a picture of your blood sugar levels over a 2-3 month time. This biomarker is used by physicians to monitor and diagnose pre-diabetes and diabetes. When we consume too much glucose—more than the body needs, that is—it stimulates fat synthesis, which also can impact our cholesterol levels.
Macronutrients: it's a balancing act
- All three macronutrients are necessary to support a healthy and active lifestyle—eliminating one or another forces our bodies into an adaptive state, which can impact our bodies (potentially even in ways still not known) in the long-term.
- These macros are all not created equally—quality is as important as quantity!
- How much you need of each varies by who you are as an individual.
- You can hack your biomarkers to see if you’re getting enough (and choosing the best sources) of macros for your health and performance goals.
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References Healthy Fat Intake | Cleveland Clinic. Cleveland Clinic. https://my.clevelandclinic.org/health/articles/11208-fat-what-you-need-to-know. Published 2019. Accessed September 11, 2019.