You’ve probably heard you need to go low carb to lose fat. Chances are other people have told you to go low fat. Right now, the ketogenic diet (a high fat, moderate protein, zero carb diet) is having a burst in popularity. All of these diets manipulate macronutrients (protein, fats, and carbs) to help you lose weight.
You’ve probably heard you need to go low carb to lose fat. Chances are other people have told you to go low fat. Right now, the ketogenic diet (a high fat, moderate protein, zero carb diet) is having a burst in popularity. All of these diets manipulate macronutrients (protein, fats, and carbs) to help you lose weight.
Low carb zealots claim that managing insulin is the key to fat loss. While the low fat crowd points out that fat is the most calorie dense macronutrient, so it should be kept to a minimum.
In recent times, the low carb group has been the most vocal. Their argument is largely based on the Insulin Hypothesis by Kevin Hall, Ph.D which states, “Diets high in carbohydrate are particularly fattening due to their propensity to elevate insulin secretion. Insulin directs the partitioning of energy toward storage as fat.”
The Role of Caloric Deficit
Back in the 1980s and 90s fat was the bad guy. So, for well over 30 years, people have been blaming individual macronutrients for the increasing fat gain we see all around us.
Despite this fascination with macronutrient ratios, recent research suggests that, from a body composition standpoint, macronutrient ratio has much less impact than we thought, that is if calories are controlled. Of much more importance than the ratio of macronutrients you consume is that you are in a calorie deficit. If you cannot achieve a calorie deficit, you will not lose fat no matter what clever macronutrient ratio you have in place.
To be honest, any differences reported in the scientific literature on varying macronutrient ratios for fat loss are of minimal impact. Picking a plan that puts you in a calorie deficit and that you can stick to is the real key.
If you are more likely to follow a higher carb diet then you will have more successful fat loss because it is a diet you can maintain. Likewise, if you prefer a higher fat intake then results will be better on a high fat diet (assuming the same calorie deficit is maintained) because you are more likely to adhere to it.
Eric Helms does a phenomenal job in his books, Muscle and Strength Pyramids, of highlighting the hierarchies of needs that exist within both training and nutrition. When it comes to fat loss, calories are king.
Consume fewer calories than you burn and you will lose fat. With that said, manipulating macronutrients to optimal levels does provide some benefits. These benefits are both physiological and psychological.
Protein, Your Fat Loss Hero
Protein can provide both physiological and psychological benefits.
Firstly, physiologically consuming relatively high protein is beneficial for fat loss. Protein provides a metabolic advantage when compared to carbs and fat.
This advantage is due to the thermic effect of protein. The amount of energy burnt by the body to digest food is known as the Thermic Effect of Feeding (TEF). Protein has a higher TEF than carbs or fats. Roughly 20% of the calories from protein are used for digestion. For carbs it is between 5-10% and fats are only 2-3%.
Secondly, protein is also the most satiating of the macronutrients. As a result, you feel fuller when eating high amounts of protein. From a psychological standpoint, it is much easier to stick to a diet if you are not constantly hungry. Willpower is not taxed to the same degree if you are generally quite full from your food as opposed to counting every second until you can eat again on less filling diet plans.
Carbs or Fats – Which Is the Devil?
When protein intake is matched, low carb diets show no metabolic advantage over higher carb diets and in many studies. Overfeeding studies have shown that people tend to gain more fat following a high fat versus a high carb diet in spite of the fact that fat utilization (burning) increases with high fat diets.
How can this be?
It most likely boils down to energy balance. As previously mentioned, carbs have a slightly higher TEF than fats. As a result, more energy is burnt through digestion on the high carb diets, as compared to high fat diets. This creates a bigger calorie deficit and, low and behold, more fat is lost. This goes a long way to debunking the insulin hypothesis.
In research funded by ketogenic (low carb) proponents it was actually found that although insulin levels did go down and fat oxidation increased on a low carb diet, this did not result in more fat loss.
Shockingly, the study stated that it took participants 28 days to lose the same amount of fat on the low carb diet as it took them to achieve in 15 days on the high carb diet. Furthermore, the participants lost muscle in the low carb group. That is not good news for low carb diets.
So, once you’ve created a calorie deficit and set protein intake to be moderately high, the ratio of fats and carbs is not extremely significant.
There is a slight trend to lower fat and higher carb intakes being beneficial for fat loss. Another benefit of keeping carbohydrates higher than fat is that energy will be higher and the fuel for high intensity exercise (muscle glycogen) is more readily available.
As such, you can train harder. Training harder means you can burn more calories and create a bigger calorie deficit, which will lead to greater fat loss.
Setting Your Protein Intake
It appears that anything between 2.3 and 3.1g per kg of lean body mass is adequate for protein intake. This is enough to retain muscle while dieting.
It also provides high levels of satiety without reducing the total number of available calories for carbs and fat enough to negatively affect energy levels. Going above this level has not been found to be more anabolic. Thus, it is unlikely to help you build muscle, highly unlikely in a substantial calorie deficit, anyway.
If your fat loss plateaus and you do not want to reduce food intake or increase energy expenditure, then you could consider increasing protein to the upper end of the range 3.1g per kg (some research shows benefits of going as high as 3.4g).
Eating this much protein could enhance fat loss because of the increased TEF. It is important to note this won’t suddenly fast track your fat loss, but may slightly increase it. The research is not conclusive at this stage and protein intake at this level has only been associated with greater fat loss due to the higher thermic effects.
Association does not equate to a guarantee of efficacy. Neither does it imply causation. Nonetheless, there is a correlation. If you are looking for every available marginal gain then high protein intakes could help your fat loss efforts.
How Often Should You Eat?
My general recommendations for eating frequency for fat loss and muscle gain are the same. I suggest you eat 4-6 meals a day based on your schedule and preference.
Intermittent fasting (IF) protocols where you go for extended periods of time (e.g., 16 hours) without eating can be effective for fat loss. In these situations, meals per day drops to 2 or 3. IF for fat loss is a whole other article though, so I’ll save that for another time.
Spreading your calorie (and importantly protein) intake over multiple meals through the day is advised because it spikes protein synthesis repeatedly through the day. This allows for peaks and troughs in MPS which has been found to be optimal when compared to trying to keep MPS constantly elevated through more frequent meals.
Eating 4-6 meals is also superior to very infrequent meal plans because there is an upper limit to how much protein synthesis can be stimulated in one sitting, regardless of protein content of that meal.
Eating more protein will not push MPS past this threshold. Given MPS remains elevated for about three hours after a meal, it makes sense to consume another meal roughly three hours later. Based on most people’s waking hours, that translates to 4 or 5 meals per day.
Fine Tune Your Carbohydrate and Fat Intake
Given that the ratio of fats and carbs is of lesser importance than protein intake, personal preference should be the key determinant of your intake. With that said, here is some further information to help guide your choices.
Consumption of dietary fat is important for regular hormonal function, especially testosterone production. It should never be eliminated from the diet. There is not so much an optimal fat intake, but a minimum for normal hormonal function.
There is some solid scientific backing for arguments saying that fat intake should be between 20-30% of total calories to optimize testosterone production. I generally suggest that clients eat 1g/kg of fats when dieting. This is an easy number to remember and will support their needs. Once protein and fats are set then carbs make up the rest of your total calories.
Carbs, like fats, have a positive impact on hormones. They are also the dominant source of energy for the central nervous systems (CNS) and high intensity athletic activities (e.g., lifting weights).
They help to fuel gruelling training and aid in recovery. Approximately 80% of your weight training is fueled by glycogen stores (stored carbohydrate). Low glycogen will impair your training and recovery.
Eating sufficient carbs allows you to train at a higher intensity, train with higher volumes, and recover quicker. They also have anti-catabolic and anabolic effects. As such, carbs are a huge advantage to hard-training individuals.
Remember, the most important things that need to be in place in order to lose weight are that you are in a calorie deficit and that you can stick to the plan. The above guidelines are just that, a guide. Adjust them to suit you. These are simply my preference, and I often tweak them to suit the needs of different clients.
Macronutrient Individualization
Consider the following variables when setting your macro ratio when you eat low carb or low fat:
- What are your energy levels like?
- How is your motivation?
- What is the status of your mood?
- What is your appetite like?
- How is your digestion?
- What is your current performance like?
Also factor in:
- Previous dieting experiences (both successes and failures)
- Food preferences
- Your sleep (Carbs before bed can help to improve sleep. Lack of sleep makes you more likely to crave carbs.)
- Stress levels
- Social flexibility
- Current body fat (In general the fatter you are, the less well you tolerate carbs.)
- Training frequency and volume (The more training you do, the more carbs you’ll need.)
Nutrient Timing
It matters. Just not as much as total calories or macronutrients. With that said, in a deficit you should bias your carbs to be peri-workout to support training performance, recovery, and glycogen replenishment.
Carbs post-workout will also help to reduce cortisol levels. Cortisol is a stress hormone which is actually quite useful during training because it helps to release fatty acids for energy. However, chronically high levels are not desirable. Consequently, bringing levels down immediately after training should be a priority.
Some may say we are all special snowflakes and respond differently to different diets, but in reality, we just aren’t that different. Because of this there are general guidelines you can use to set-up your fat loss plan.
Use these to get started, but then adjust as needed based on your results. Do not be handcuffed to these recommendations. If they are not working then you should tweak them to find something that does.
References:
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