Why set and forget calorie and macro targets will fail you

Set and forget calorie targets rarely work.

But the good news is, you can actively manage your macros (carbohydrates, fat and protein) with small progressive refinement to ensure you continue to move towards your goals.

This article will show you how.

Nutrient density vs macros

While nutrient density and satiety should always be your highest priority, it can also be useful to actively manage your calorie and macronutrient intake.  

Optimisers in our Nutritional Optimisation Masterclass find it much easier to optimise their micronutrients once they get their macronutrients in the right ballpark.

The Smart Macros Algorithm uses your biometric data (i.e. body fat, muscle mass, weight and blood sugars) to empower you to progressively refine your protein, fat and carb targets as you move toward your goals, whatever that might be, including:

  • stabilising your blood sugars if you have diabetes or prediabetes, 
  • fat loss without losing too much muscle, and
  • building muscle without gaining too much fat.

Macronutrients vs micronutrients 

But before we dive into how the Smart Macros algorithm works, let’s recap some basic concepts:

  1. macronutrient,
  2. micronutrients,
  3. protein,
  4. fat,
  5. carbohydrates, and
  6. calories. 


Macronutrients are the major components of food that make up the food we eat and provide us with energy (macro = big).  

The main macronutrients are protein, carbohydrates and fat.  

While there is plenty of debate about which macro mix is optimal, the Smart Macros Algorithm can help you find what works for you (note: macro = large).   


Micronutrients are the vitamins, minerals, amino acids and fatty acids that our body needs to thrive (remember: micro = small).  

Micronutrients don’t necessarily provide much in terms of energy, but if you don’t get the nutrients you need, your cravings will increase, and you will end up eating more as your body goes in search of enough of the essential micronutrients to survive and thrive.  

Our satiety analysis food logging data from Optimisers shows that we tend to spontaneously eat less when we consume foods that have a higher nutrient density (as measured by the Optimal Nutrient Score).  

Nutrient density is simply the amount of micronutrients per calorie of food that you consume.  

We created Nutrient Optimiser to help people identify the foods and meals that contain more of the nutrients that you are finding harder to get in your diet. 


The word protein is derived from the Greek word proteus, which means primary or of first importance.  

While protein can be used for energy if there is insufficient energy coming in from carbs and fat, protein is primarily used to build and repair your muscles and organs.   Amino acids are critical to our neurotransmitters that make your brain operate and the many of biological functions that keep your body running.  

While you need adequate protein to survive, protein is not a great source of energy.  You lose around 25% of the calories in protein when you convert it to ATP to use for energy.  This is known as the Thermic Effect of Food.  You may feel hot and need to drink more water if you try to overeat protein.

Your appetite drives you to get enough protein.  However, you will struggle to overeat protein because it is difficult for your body to convert protein to glucose (gluconeogenesis) or to store as fat (lipogenesis).   

Protein is critical to satiety and controlling your hunger.  Your appetite sends out a strong ‘full’ signal once you consume adequate protein.  

Our satiety analysis has shown that we tend to eat fewer calories when our diet has a higher percentage of protein.  It’s important to note that it’s not merely about eating MORE protein, but rather a higher percentage of protein (i.e. with less easily accessible energy from refined fat and carbs).


Carbohydrates are a fast-burning fuel source that your body uses for explosive activities.  

You may benefit from more carbohydrates in your diet if you are very active and doing a lot of explosive activity.

If you don’t have access to dietary carbohydrates, your body can make glucose from protein. When your carbohydrate intake is low, ketones can also be made from fat to fuel your vital organs (e.g. brain and heart).

There is limited storage capacity in your body for carbohydrates, so they get used before fat.  Carbs also have a higher oxidative priority and are more volatile, so they need to be used as a priority before dietary fat or body fat.

If you’re eating more carbohydrates than your body needs you may see elevated blood glucose levels, especially if you have higher levels of body fat (e.g. as is often the case in prediabetes or type 2 diabetes).  

While elevated blood glucose is a sign that you are probably consuming too much carbohydrate, it can also be an indication that your fat stores are approaching capacity and the fuel in your body is backing up.   

Like an intersection gets congested when it is flooded with cars from every direction at the same time, our body tends to get flooded with energy when it is getting multiple fuel sources at once.


Fat is ideal for storage and everyday use when you’re not running around at super high intensity.  You only lose about 3% of the energy from fat when you store or burn it for energy (compared to around 7% for carbs and 25% for protein).  

While many of us want to lose some fat from our body, your body likes to hold on to fat for a possible emergency when food is scarce.  You will only use your body fat once the alcohol, ketones, protein, carbohydrates and dietary fat in your system are used up.


A calorie is a measure of the potential chemical energy in the food you eat.  

By definition, a calorie is the amount of energy required to raise one gram of water by one degree Celsius when burned in a calorimeter

But we don’t exactly ‘burn’ food in the same way we measure it in a calorimeter, so the calorie value of the food you consume doesn’t perfectly correlate with the amount of energy you will get from the food you eat.  

Calories can only ever be seen as an estimate of the amount of energy that we get from our food.  

As noted above, there are various losses of calories when your body uses them for energy (due to diet-induced thermogenesis) from each of the macronutrients (i.e. 25% for protein, 7% for carbs and 3% for fat).  So, thinking simply in terms of calories in vs calories can be problematic.  

The reason that we eat more calories than we need to (i.e. the satiety value of our food) is arguably more important, more interesting and more useful in practice.

Rather than simply managing calories, it can be more useful to manage your macronutrients (i.e. protein, carbs and fat) to make sure you are getting what you want from your diet and dialling in the satiety value of your food to align with your goals (e.g. weight loss, weight gain or maintenance).  While we can count calories and try to eat less or more, in the end, our appetite generally wins out.

As a rule of thumb:

  • If your blood sugars are elevated after meals and highly variable, you likely need fewer carbs
  • If you’re losing too excessive amounts of muscle mass you need more protein; and 
  • If you’re not losing fat from your body, you probably need less fat in your diet.

The problem with set and forget macro calculators 

There are plenty of ‘set and forget’ macronutrient calculators out there.  But they’re all ultimately just guesstimates.  

There is no way that a theoretical formula can accurately account for all the factors that are at play when it comes to quantifying how much energy your body uses due to: 

  • changes in your activity levels, 
  • changes in non-exercise thermogenesis and metabolic adaptations to long term dieting or long term dieting, 
  • your blood sugars, 
  • your level of muscle vs body fat, or 
  • your inaccuracies in tracking your food. 

The calories out part of the equation is constantly changing as your body adapts to your diet, and you lose or gain weight.  Not only will you use less and less energy as you get lighter and lose metabolically active muscle, but your body will also learn to adapt and survive on fewer calories.

If you are trying to lose weight sustainably and successfully, you really want to be eating as many calories as you can while still achieving a reasonable rate of weight loss (i.e. 0.5 to 1.0% per week over the long term).  

If you cut calories too quickly, there is nowhere left to go once your body adapts to the lower intake levels.  Hence, a super aggressive calorie deficit may not be as successful as progressive changes over the long term.

And regardless of the numbers that any macro calculator gives you, few of us make radical overnight changes that actually last for the long term.  Eventually, in time, we tend to revert to old habits.  

It may not sound as glamorous as an overnight transformation, but the best way to achieve lasting results is to steadily move from where you are now towards where you want to be by making incremental improvements until you successfully get the results you want.  

Smart macros

To ensure you achieve your goals, the Smart Macros Algorithm progressively updates your macronutrient targets (carbs, fat and protein) based on your biometrics (blood sugar, body fat and weight).

Nutrient Optimiser syncs with your Cronometer account to automatically import your macro and micronutrient intake.  

You can log your weight, body fat and blood sugar data in either Cronometer or the Nutrient Optimiser

Each week the Smart Macros algorithm reviews your progress and makes incremental refinements for the coming week.  

While Nutrient Optimiser can give you starting macronutrient ranges based on the theoretical formulas, we also created a free macro calculator that you can use if you want to get an idea of what your starting macros should be.  But it is more useful to track how you normally eat and pay attention to the progressive nudges of the Smart Macros Algorithm over weeks and months.

Do I really need to track my food?

Tracking your food is not fun, and most people suck at it!   This yet another reason that set and forget calculators fail most of the time.  

Due to our optimism bias, we often underestimate our food intake.  We want to admit to ourselves that we had that cookie, so we don’t log it, we don’t log on our ‘bad days’, or we vastly underestimate our portion sizes because we don’t carry kitchen scales with us to the restaurant, school or university.

If you are super accurate and weigh and measure everything you eat, the Smart Macros algorithm will keep your intake high (which is good).  But if you track badly and underestimate your intake, Smart Macros will adapt and provide recommendations based on the data you give it.  

It’s definitely ideal to track perfectly,  but if you don’t, the Smart Macros Alogythm will compensate for your poor tracking.  

We don’t want you to track your food for any longer than you have to.  We believe in primarily focusing on food choices and quality to help you dial in your food quantity.  But if you have not been able to get the results you want, tracking may be necessary to help your dial-in our eating patterns and nudge you in the right direction until you get the results you want.

Before starting to follow the Smart Macros, we recommend that you track a few days of your normal diet as accurately as you can.  Then, going forward, you should track at least two typical days each week.

Tracking everything every day would be ideal, but a few good days of tracking is better than tracking badly every day.  

Blood sugar/diabetes

One of the most exciting applications of Smart Macros is for people with diabetes to help them find their optimal carbohydrate intake to help them balance their blood sugars.  

Understanding if your blood sugars are elevated helps you to understand if you actually need to worry about limiting your carbohydrate intake.  While the general population consumes more processed carbohydrates than is optimal, there are also many people that think that all foods that contain carbohydrates are bad and that limiting them more and more is the key to fat loss.  

Unfortunately, this line of thinking can lead to avoidance of nutrient-dense food that may contain carbohydrates in favour which are often replaced by higher fat foods and added fats which are also nutrient-poor and provide little satiety. 

The carbohydrates in your diet have the most significant impact on your short term blood sugar levels.  So, if you have elevated blood sugars (e.g. Type 1 Diabetes, Type 2 Diabetes or Prediabetes) it can be useful to reduce your carbohydrate intake to the point that your blood sugars stabilise at healthy levels.

As you track your diet in Cronometer, Nutrient Optimiser will update your carbohydrate limit each week.  If your blood sugars have been high, the Nutrient Optimiser will suggest you reduce your carbohydrate intake for the coming week.

At the same time, if your blood sugars are stable (i.e. less than 30 mg/dL or 1.6 mmol/L rise after meals), then you know your blood sugars are fine, and you don’t need to worry about limiting carbs.  This frees you up to focus on the most nutrient-dense and satiating vegetables without worrying excessively about carbs.

Our recent analysis of people using our Data-Driven Fasting system found that most people have a small rise in blood glucose after they eat and that there is no correlation with a smaller rise after meals and being more or less lean.

Don’t get too far ahead of yourself

One of the benefits of tracking your intake accurately is so your Smart Macros targets don’t get too far ahead of you.  

If you can’t manage to initially reduce carbohydrate intake, the algorithm won’t keep on recommending lower and lower carb intake until you get to zero.  Smart Macros will wait until you catch up and not set goals way beyond what you can realistically achieve or sustain.  

Getting off the blood sugar rollercoaster feels great.  Large swings in blood glucose can make you feel sluggish, depressed, grumpy or hangry.  Stable energy levels will feel amazing.  

But another benefit of managing your carbohydrate intake is that it moves you away from the hyperpalatable carb+fat zone that tends to drive us to overeat.  Moving either side of this hyperpalatable carb+fat danger zone tends to lead to increased satiety and fat loss and eventually reversal of type 2 diabetes.  

As you can see in the chart below from our analysis of half a million days of MyFitnessPal data, very few people manage to sustain a very high or a very low carbohydrate intake.  We tend to gravitate to a hyperpalatable mixture of fat and carbohydrates that tends to drive us to eat more than we would like to.

If your blood sugars are great, the Nutrient Optimiser will increase your carbohydrate limit to allow you to focus more on nutrient-dense foods and meals.  As shown in the chart below from our analysis of our series of 22 recipe books, maximum nutrient density tends to align with a lower-carb diet (but not zero carbs).

Following the recommended foods and meals provided by the Nutrient Optimiser, it won’t’ take too long to titrate down your blood sugars to healthy levels.   

If/once you have your blood sugars under control, you can start to focus on fat loss if you still have weight to lose.  

My story  

A could of years ago I started tracking a few biometrics regularly in order to test and develop the Smart Macros Algorithm.  

As you can see from the chart below, there have been a few ups and downs and periods where I have taken a break before getting back into more intense tracking.  But there is a solid downtrend.  

At 43, I am now lighter (and a lot stronger) than when I was 25!  

I was never particularly fit, lean or athletic, but as I got older, I started to gain weight.  Then I got interested in nutrition. I figured the last thing the world needed was another fat diet guru, so I thought it was time I put my theory into practice.

When losing weight, maintaining muscle is a real issue that you should ideally actively manage.  While it’s hard to measure body fat accurately, tracking using bioimpedance scales that are quite common and cheap these days allows you to do it regularly so you can see real trends over time.  

The chart below shows my body fat % using my bioimpedance scale at home.  While the numbers bounce around from day to day, you can see a definite trend.  

The chart below shows my body fat in kilograms calculated from my weight and body fat %, showing a little less scatter.  When you are losing weight, holding onto your lean muscle mass is very important!   

Since then, it’s been awesome to see many other Optimisers make great progress as they dial in their targets using the Smart Macros Algorithm. If you’re interested you can check out the stories below.

The Nutritional Optimisation Masterclass 

The Smart Macros algorithm is a central component of the Nutritional Optimisation Masterclass and is built into Nutrient Optimiser

While the primary goal is to guide people to dial in their nutrient density to enable healthy appetite control without tracking in the long term, we have found the Smart Macros Algorithm to be extremely helpful to help people dial in their macros during the Masterclass.  

If you’d like to join us, the next 6 Week Nutritional Optimisation Masterclass starts on 7 November 2020.  You can sign up here to be a part and start your journey of Nutritional Optimisation using Nutrient Optimiser and the Smart Macros Algorithm.

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