While it may sound too good to be true to lose fat while eating unlimited amounts of food, it is possible. In this evidence-based article, you will discover how you can become leaner while following such an ad libitum diet.
What is an Ad Libitum Diet?
Even though the term ‘ad libitum’ may sound elaborate, it is not that special. In fact, most people follow an ad libitum diet. That is because such an eating style means you eat when you are hungry and stop when you are full.
Thus, on ad libitum diet you do not try to hit a particular calorie or macronutrient target. Instead, you eat based on your level of satiety, meaning that you can eat as much food as you want.
Can an Ad Libitum Diet Help You Lose Fat?
If you approach an ad libitum diet the way most people do, then the answer tends to be no. You will not lose fat on an ad libitum diet. In fact, you are more likely to gain some.
However, if you approach an ad libitum diet the right way (we will show you how to do that shortly), then you can become leaner while eating to your heart's content.
That is because lowering the number on your scale comes down to one thing: energy balance. All you have to do to lose weight is to take in fewer calories than you burn.(1)(2)(3)
It doesn’t even matter whether you consume your calories in the form of dietary fat, carbs, or protein. As long you are in a calorie deficit, you will lose the same amount of weight regardless your macro ratios.(2)(3)(4)(5)
This means that if you can set up your ad libitum diet in such a way that you consume fewer calories than you burn, you will be guaranteed to lose weight. The only question is:
How Can You Maintain an Energy Deficit on an Ad libitum Diet?
The answer is to follow a diet that is highly satiating for the number of calories it provides. In other words, you consume foods that score high on the satiety index, but avoid those that are ineffective at curbing hunger.
Improving the satiety index of your diet in such a way will help you slim down by automatically causing you to consume fewer calories, usually to such an extent that you will end up in a calorie deficit.(6)
You see, your appetite is genetically fixed. It is as if you have a daily appetite meter you must fill to satisfy it. And each food you consume fills a particular portion of that appetite meter per 100 calories.
The thing is that some foods fill much of the appetite meter while others do not. Research shows, for instance, that potatoes are seven times more satiating than croissants.(7)
Therefore, when you eat 500 calories of potatoes instead of croissants, you will fill much more of your appetite meter, which aids weight loss by reducing your total calorie intake.
That’s why research shows that high-satiety ad libitum diets are effective for fat loss without the need for calorie counting. (Such diets automatically get you into a calorie deficit.)(8)
A one-year trial on overweight and obese women, for instance, found better weight loss results on high satiety index diets than on the Standard Care weight loss approach of the National Health Service (NHS).(9)
How the Satiety Index of Your Diet Influences Your Calorie Intake
A study published in the American Journal of Clinical Nutrition looked at the difference in appetite and calorie intake between high- and low-satiety diets.(10)
For the study, scientists instructed twenty obese and non-obese subjects to follow two different diets, each lasting five days.
First, the subjects could eat ad libitum on a low-satiety diet. This diet contained foods with minimum bulk but lots of simple sugars and fat; for example, bacon, orange juice, and white toast with margarine.
Then, the same subjects could eat as much as they wanted on a high-satiety diet. This diet contained foods that had less sugar and fat but more fibre, such as fruit and salads.
The result?
The participants felt full on the high-satiety diet after consuming an average of 1,570 calories, but to reach that same fullness on the low-satiety diet, they had to take in 3,000 calories.
In other words, on the high satiety diet, the subjects had to consume about half the calories to feel satisfied.
How to Lose Fat on an Ad Libitum Diet
As covered thus far, the key to ad libitum dieting is to follow a high-satiety nutrition plan. What follows are five tips to make your diet highly satiating so that you will end up in a calorie deficit and lose weight.
1) Increase your protein intake
Protein is highly satiating. That is why consuming more of this macronutrient helps you to lose fat by automatically reducing your total calorie intake.(9)(10)
To get enough protein, aim for at least 0.73 grams of protein per pound of body weight per day. Thus, if you weigh 165 pounds, that is at least 120 grams of protein or more.
Get that amount primarily from lean protein sources such as chicken, egg whites, tuna, seitan, tofu, Quorn, and protein powder since such low-calorie sources are best for helping you to control your total energy intake.
2) Cut simple sugars from your diet
Since sugar has almost no satiating effect, sugary calories tend to go on top of the energy you already consume. That’s why cutting all processed sugars from your diet will automatically reduce your calorie intake by a great deal.(11)
You do not, however, have to avoid the sugars in whole fruits. Such sugars are fine to consume because fruit contains various compounds that benefit health and aid weight loss, like fibre, water, and micronutrients.
3) Rid your diet of high-fat foods
It is best to limit your dietary fat intake on an ad libitum diet to about 20% to 35%. That is because fat is the least satiating macronutrient while containing the most calories.(12)
What we recommend is that you exchange high-fat food for lower-fat variants. For instance, replace your full-fat yoghurt with one that is fat-free, and substitute full-fat beef with lean cuts.
4) Get more fibre and make fruit and vegetables the staples of your diet
Fibre is highly satiating. Research shows that for every 14 additional grams of fibre you consume, ad libitum calorie intake reduces by around 10%. That is why increasing your fibre intake helps you lose fat.(13)
Regarding the amount of fibre to consume, men should aim to get at least 38 grams of fibre per day, while women should aim for at least 25 grams per day.
Source the vast majority of that amount from fruit and vegetables by making these food sources the foundation of your diet. That is beneficial because both help you lose fat owing to their high fibre but low calorie content.
5) Drink more water, especially before your meals
Another powerful way to streamline your fat loss efforts is by drinking more water. Research shows that habitual water consumption reduces calorie intake by an average of 9%.(14)(15)(16)(17)
It is particularly helpful to drink water before your meals. So found one study that drinking 500 ml of water 30 minutes before breakfast lowered calorie intake by 13%.(18)