Having talked about calories and protein, it makes sense to mention the remaining macronutrients; fats and carbohydrates. While it isn’t necessary to micromanage your intake of either (stick to your set calorie target based on your TDEE and make sure you’re getting enough protein and the rest will take care of itself), it is useful to understand why this isn’t important!
Fats
Fats have had some pretty bad PR over the years, and while it is true that too much fat can lead to problems with cardiovascular disease and strokes, too little fat can lead to problems with dry skin, brain health and vitamin deficiencies.
Fats are made up of chains of fatty acids of differing lengths, joined to a molecule of something called glycerol. They are broken down into these raw materials during digestion and once absorbed into the blood from the gut, they can be recombined into new combinations to make new fat molecules for use in cell membranes, hormones and other chemicals. Fats are also a great source of energy, supplying more than twice the amount of energy as the equivalent amount of protein or carbohydrates. This also means however, that any excess fat can easily supply you with too much energy, leaving you in an energy surplus and more likely to store this extra fat.
Carbs
Carbohydrates are the starch, sugar and fibre molecules found in foods. All carbohydrates are made up of sugars. Fibre is not able to be broken down in our bodies during digestion, but starch and sugars are broken down into glucose. This glucose can then be used by our bodies to release energy during respiration. Any glucose not used by the body at any one time can be taken into the muscles, converted into something called glycogen and stored ready for when the muscles next require energy (the glycogen is broken down back into glucose and used in respiration).
How much of your diet should be made up of each?
A simple google search will recommend anything from an ultra-low-fat diet, to the ketogenic diet, with minimal carbohydrate intake, and everything in between. But really, it comes down to personal preference. If you like foods that tend to be predominantly fat-based, then eat a high-fat diet; if you like bread, pasta, rice, sweets etc, then aim for a higher carbohydrate diet. At the end of the day, multiple trials, (a particular favourite is the DIETFITS study) have shown that there is no difference between weight-loss from a low-carb high-fat diet and a low-fat high-carb diet (all other aspects of the diet being equal). The real factor comes down to how well you train and your adherence to the diet itself. In other words, if you really like to eat carbs and you will therefore struggle to stick to a diet in which you have to cut them out, you won’t have success. Also, if cutting out carbs leaves you feeling sluggish and low on energy in the gym, you won’t train as hard and therefore won’t get the results that you want.
Some rules however!
While it is essentially a matter of preference for the overall fat and carbohydrate content of your diet, there is a minimum fat content that every diet should include, because of their role in forming cell membranes and making hormones. You should aim for a minimum of 20% of your calories coming from fat;
e.g. an individual with a calorie target of 2000 should aim for at least 45g of fat per day [(2000 x 20%) ÷ 9].
You can of course include more than this, but in order to balance out your calorie intake, carbohydrate intake would need to decrease.
How to fit your preference into your calorie requirement.
The only thing you need to remember when it comes to deciding how much fat or carbohydrate to eat, is that a gram of carbohydrate contains 4 calories and a gram of fat contains 9 calories. This means that if you increase your fat intake by 10g, your carb intake must decrease by 20g to counteract the calorie increase. As a final note, your carb and fat intake don’t have to be the same every day, some days you might want high carb and minimal fat intake, while other days you might go the other way. The only thing to be aware of in this case is that when you have a higher carb day, your muscles will naturally store more water (every g of carbohydrate absorbed by your muscles is associated with 4g of water). So any weigh-ins could be affected.
Summary
· Base your food choices on personal preference (if you like fatty foods, have a high fat intake; if you like carbohydrates and sugary foods, aim for a high-carb diet).
· For good health, fats should never make up less that 20% of your calorie intake (at 9 calories per gram).
· There is no difference in weight loss progress between high-carb and high-fat diets.