In my 12 years as a practicing nutritionist, I’ve heard it all: carbs make you fat. Plant-based diets are the key to weight loss.  Six small meals a day keeps your metabolism running.  There are no shortages of people, media, and Instagram accounts admonishing what is healthy and what is not with almost religious fervour (and you can find directly conflicting “evidence” from both camps, if you look hard enough).

The problem is, dietary “common knowledge” is constantly changing.  What was generally accepted as true even five years ago within the dietetic community can be completely outdated now (remember when people were avoiding eggs because of cholesterol worries?  Or eating “low-fat” cookies packed with sugar?).  Secondly, what is “true” for one person may manifest as the exact opposite for the next (for example, gluten would completely poison someone with celiac disease, while on the other hand, bread and pasta might provide optimal fuel for an ultramarathoner).

So how does your average person wade through the minefield of nutritional advice without getting completely lost – or worse, stuck believing in misinformation?

Thankfully, there are some fundamentals that hold true across biological, physiological, nutritional, and even psychological science. At their core, all healthy diets:

  • are based on the principle of caloric deficit (energy balance; calories-in-calories-out)
  • include mainly – but notably, not exclusively – whole foods
  • promote proper hydration and electrolyte balance
  • allow for an element of discord / “messing up” from time to time

I want to talk you through these one by one so that you can get a sense of what lifelong healthy eating really looks like:

CALORIC DEFICIT.  General thermodynamics states that if a living organism consumes less fuel than it outputs, it will typically decrease in mass.  The opposite is also true.  And while calorie counting in humans is an inexact science, the basic principle of moving and burning more than one eats and absorbs holds water across ages, races, and genders.  If you’ve tried a diet in the past and not lost weight, you were very likely overeating.  If you’ve recently made changes to your diet or exercise that have resulted in weight loss, it is probable that you created a larger deficit than you previously were.  It’s as straightforward as that.  Not sure what you’re consuming – or burning?  I recommend that in the early days of learning about energy balance, clients invest in a movement tracker (such as an Apple watch or Fitbit) and use a log (such as MyFitnessPal) to chronicle their food intake.  This way, you can put data behind your efforts and get a clearer picture of why and how you are moving toward your goals.

WHOLE FOODS.  What is a “whole” food?  The easiest way to distinguish a whole food from a processed one is that it looks (mostly) like it does growing in nature – often this means foods outside of a box, bag or package.  When your diet is made up mainly of nature’s versions of food (think apples versus applesauce; chicken breast rather than chicken nuggets; peanuts as opposed to peanut butter cups), there’s a good chance you’re getting the full nutrient profile, fibre content, and fewer calories from that food.  So why say “mostly” and not “exclusively” whole foods?  There are some forms of processing, fermentation for example, that can actually improve the nutrient profile of a whole food – turning cabbage into kimchi, for example, or iron-fortifying cereals.  When choosing the composition of your overall diet, prioritise about 80% of your meal from lean meats and fish, fresh vegetables and fruits, and whole grains – but leave about 20% for the fun stuff, as well (more on this later).

HYDRATION AND ELECTROLYTE BALANCE.  Many of my clients struggle with processing their food (think digestion, absorption and elimination) due to dehydration and/or improper electrolyte balance.  Healthy adult women should aim to drink at least 2.2 litres of plain water daily; for men this target rises to 2.5 litres and for those who are highly active, living in humid or hot environments, or pregnant and breastfeeding, that recommendation reaches 3 litres.  Water can also come from foods; some of the best sources of food-based hydration are cucumbers, tomatoes, spinach, broccoli, and oranges.  Additionally important is keeping your electrolytes in balance – this means not only drinking enough water, but also maintaining your sodium, potassium, and calcium levels.  If you regularly experience dizziness, cramps, or fatigue, imbalanced mineral levels can be to blame.  Consider integrating a sugar-free electrolyte tablet (such as Hydrolyte) or 100% coconut water into your daily hydration strategy, and be watchful of your intake of diuretics (such as coffee and tea) that may affect your ability to stay hydrated.

PLAN TO “FAIL.”  While I don’t consider things like eating a cupcake or having too much alcohol “failures,” for someone looking to make better nutritional choices, these relatively minor events can seem derailing – and lead to a downward spiral of unhealthy behaviours.  I encourage anyone seeking to initiate a nutrition overhaul or new diet to plan for what will (inevitably, we’re all human) happen when you mess up.  I mean it – mentally rehearse how you will react when you fall off the wagon, and design a damage control strategy to get you back on track as quickly and guilt-free as possible.  Often, what would’ve been a small slip-up (a pizza night out with friends) snowballs into a few more days of poor choices (“well, I’ve already had the pizza….so why not go out for ice cream?”) or worse, a complete abandonment of the habits you worked so hard to develop to make the initial change.  When you prepare for the bumps in the road, you develop a mindset of resilience, determination, and consistency, no matter what comes.

Sure, there are literally hundreds of additional factors that factor into what makes a particular way of eating “optimal” for a particular person – for example, vitamin deficiencies, allergies, medical conditions, hormone profiles, genetic and epigenetic risk factors, and lifestyle preferences.  This is why it is crucial to meet with a certified nutritionist or registered dietitian to discuss your personal health profile and develop an eating plan that works for your body, goals, and lifestyle.  But in general, if you’re looking for ways to begin improving your diet today, the four fundamentals outlined here are a solid, evidence-based place to start.

By Amanda Lim, Founder & Director at Peak Health Consultancy at