What are macronutrients?

16 September 2020 Sophie Scott
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Calories in verses calories out, right? So, where do macronutrients fit into this equation?

In the fitness industry, it’s popular to count calories and macronutrients in food, but does this work for weight loss, or is it a big waste of time? Let’s investigate.

What are macronutients?

Macros, short for macronutrients, are the nutrients we need in large amounts. Micronutrients (although no less important) include vitamins and minerals and are needed in much smaller amounts. Macronutrients can be broken down into three subgroups: carbohydrates, fats and protein and are measured in grams. All the macros are essential, playing different roles in the body. For example, our bodies rely mainly on carbohydrates as the preferred source of energy.

Carbohydrates can be further divided into simple and complex carbohydrates, depending on their chemical structure and physiological effect. In short, it’s important to aim to obtain most of your energy intake from complex carbohydrates. They can take longer for your body to digest, keeping you fuller for longer, plus are packed with fibre which is important for gut health. Win-win! Think vegetable stir-fry and rice, porridge or hummus and wholegrain crackers.

Lipids include fats (solid at room temperature – like butter) and oils (liquid at room temperature – like olive oil). Commonly, the term “fats” is used when referring to both fats and oils. Fats can be an energy source if carbohydrate intake is low, fat insulates against temperature extremes and forms part of cell membrane structures.

Proteins provide the body with the amino acid building material for building cell tissue, form hormones and support immune function. They can be sourced from both animal and plants. Animal protein contains all the nine essential amino acids and are therefore classed as ‘complete’ proteins. Plant foods are deficient in one or more of the essential amino acids and are classed as ‘incomplete’ proteins. It doesn’t mean one is better than the other, simply that to obtain the full spectrum of amino acids required by the body, it’s important to eat a range of foods and, if you’re vegan, obtaining protein from a diversity of plant sources is key. Foods high in protein include meats, chicken, fish, milk, eggs, yoghurt, cheese, tofu, nuts and seeds.

The recommended daily intake (RDI) for men is 0.84g/kg body weight and 0.75g/kg body weight for women. However, new research released by the CSIRO supports an increase in protein intake of 1.2-1.6g protein/kg bw, especially for overweight Australians who are seeking to lose weight.

In summary, the National Health and Medical Research Council recommends the following percentage energy balance to reduce chronic disease risk:

  • 40-65% from carbohydrate
  • 20-35% from fat
  • 15-25% from protein

So why do people want to alter their macro intake?

The perception is that if you change up the macro intake, for example, eat less carbs than recommended and more fat (like the keto diet) you’ll lose more weight than just reducing total energy intake across the board. However, the research doesn’t support this. In fact, numerous studies indicate no significant difference in weight lost between low fat and low carbohydrate diets. Other studies confirm that when people just eat less, weight loss occurs regardless of macronutrient ratio.

The keto diet requires reducing carbohydrate intake to a low 5-10 percent of total intake and cuts out significant food groups. Research indicates there’s no difference in weight loss between keto and energy restricted diets (i.e. just reducing the amount you eat in total) (O’Neill, 2018).

What is the macro breakdown of some common foods?

Most foods contain a mix of all the macronutrients; however, the proportions will differ. For example, meat contains mainly fat, but also some protein, water and other nutrients.

The macronutrient distribution of selected foods:

Food (per 100g) Carbohydrate (%) Fat (%)
Protein (%)
Almonds 16 50 20
Avocado 8 13 1.6
Banana 21 0.3 1.4
Beef (65g cooked) 0 36 10
Oats 10 2 2
Watermelon 8 0 0.6
Yoghurt (plain) 5 3 5

*Australian Food Composition Database.

Note: The remaining % of the food composition includes water and other nutritional components. Fruits and veggies typically have a high water content.

How do you count macros?

Macros must be listed on food labels according to the Food Standards Code. So, you’ll see the values on the nutrient information panel on any packaged food. There are many apps, such as myfitnesspal  that assist in counting macros and calories and draw from both government databases and user generated data. You would tally up all the macronutrients in the foods you eat in a day and then compare them to the ratios set.

Do you need to count macronutrients for weight loss?

No. In fact, counting macros and calories can be very inaccurate for the following reasons:

  1. Calorie counts on labels and databases are averages, so the true calorie count of what you’re eating may be higher or lower.
  2. Not all of the calories (or macros) are absorbed. For example, only 85 percent of the kilojoules in almonds are actually absorbed by the body, the rest of the fat in almonds is bound up in fibre and passes straight through.
  3. Cooking increases the amount of calories absorbed, and labels may not reflect this.
  4. We’re typically not very good at estimating how much we eat. For example, was that one tablespoon of peanut butter or a heaped tablespoon? The calorie count can be significantly different to our estimates.
  5. Each person absorbs different amount of macros and calories from foods according to their individual gut microbiome composition. So, the values on the labels and in the apps may not reflect the precise amount of energy you will derive from the foods eaten.

If we eat a whole variety of foods from the five food groups, we’ll obtain sufficient amounts of each of the macronutrients without the need to count anything.

Counting calories can be an interesting exercise if you’re wondering if you are close to your energy requirements or way over. For example, for a moderately active 32-year-old female, energy requirements are 7600 kJ per day. So, counting calories for a day may indicate how close to the requirements they are.

Obsessing over numbers can result in people losing touch with intuitive eating. It’s best to treat our food as a whole entity, rather than breaking it down into its nutritional components. Plus, how do you even macro count the pizza you had out with friends?

Summary

Calorie counting can be imprecise and stressful, and is rarely necessary. Truth is that most people won’t count calories for more than a few weeks. Why? It’s boring, inaccurate and, let’s be honest, there are many things we can do with our time rather than spend it counting calories and macros in our food!

Also, this form of monitoring could be viewed as just another form of dieting, and dieters are six times more likely to develop an eating disorder. So, the long term implications of continual calorie and macro counting may, in fact, be quite harmful.

The message is increasingly clear: rather than fiddling around with macronutrient distribution in an aim to avoid weight gain in our population, it is more productive to focus on the overconsumption of energy rich junk foods and soft drinks outside the food groups recommended in the Australian Dietary Guidelines (as well as moving more).

References

Food Standards Australia New Zealand (2019) Australian Food Composition Database
Gardner, C. et al (2018). Effect of Low-Fat vs Low-Carbohydrate Diet on 12-Month Weight Loss in Overweight
Adults and the Association With Genotype Pattern or Insulin Secretion. JAMA, 319(7), 667.  https://doi.org/10.1001/jama.2018.0245
Ketogenic diet, Fad or Future. Professional Development Seminar, Matt O’Neill APD.
NHMRC. (2006). Nutrient Reference Values | for Australia and New Zealand. Retrieved from https://www.nrv.gov.au/
Noakes, M. (2018). Protein Balance: New concepts for Protein in Weight Management.
Sacks, FM, et al 2009, ‘Comparison of Weight-Loss Diets with Different Compositions of Fat, Protein, and Carbohydrates’, New England Journal of Medicine, vol. 360, Massachusetts Medical Society, no. 9, pp. 859–873, <http://www.nejm.org/doi/10.1056/NEJMoa0804748>.
Tomiyama, A. J., Mann, T., Vinas, D., Hunger, J. M., Dejager, J., & Taylor, S. E. (2010). Low calorie dieting increases cortisol. Psychosomatic Medicine, 72(4), 357–364. https://doi.org/10.1097/PSY.0b013e3181d9523c

Sophie Scott

Senior Trainer/Assessor – Nutrition and Dietetics

Sophie is passionate about nutrition, fitness and behaviour change coaching. As a Registered Nutritionist, Sophie takes a wholistic approach to nutrition, focusing on people’s relationship with food, driving a shift to a healthier approach to eating.

Sophie has worked as Personal Trainer and Group Ex Instructor for many years. She has taught a range of group fitness classes from yoga and pilates to Zumba™ and bootcamp. She started teaching at a gym in Vanuatu, then moved to Wellington, New Zealand to launch her own business, fitandfed, focusing on women’s health and fitness, before moving back home to Australia.

Now the Head Trainer - Nutrition at FIAFitnation, Sophie inspires the next wave of fitness professionals and nutrition coaches.

She has extensive experience in the education field, initially working in the area of environmental education, assisting people green up their lives, before moving into the health and fitness industry. Sophie has also presented and written scripts for a number of media outlets including the Eco Reno series on Channel 7’s Sunrise program.

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