How To Lose Body Fat Safely

So let’s say you are healthy, your hormones are in balance, you eat enough food on a daily basis (Exactly How Much Should I Eat), and you decide that you want to lose some body fat. How do you do it without putting yourself in a “metabolic shit hole” or affecting your health in a negative way?

First of all notice the title of the article. It addresses losing body fat. That’s our goal right? There are ways to burn muscle but unless it is for a sport specific reason (i.e. getting into a lower weight class for certain sports) I wouldn’t recommend it. If we want to lose weight for health or aesthetic reasons we want to focus on burning fat only.

To burn fat there needs to be an imbalance between caloric intake and caloric expenditure. Essentially a deficit needs to be created. This can be done very slowly, or more quickly depending on the goal and how much body fat needs to be lost.

There are two ways to create a deficit. Exercise and diet. You can also combine them. For example, if you need to create a 500 calorie daily deficit you could potentially cut 500 calories from your meals, or you could do 500 calories of extra exercise, or finally do a combination of the two in which case you may cut 250 calories worth of food and increase your exercise output by 250 calories.

Note that you also don’t necessarily need to create a calorie deficit through actual exercise. You could increase your daily activity. You burn calories every day during the course of every day life. It is called Non-Exercise Activity Thermogenesis. By becoming more active all day, every day, you may end up burning more calories versus just going to the gym for an extra hour. The calories you can burn in an hour are probably less than what you can burn throughout the entire day by increasing your activity (i.e. taking the stairs instead of the elevator).

Back to this deficit? Is it better to create one through exercise or through decrease in calories? There are a few factors to consider.

For a woman with a normal menstrual cycle, studies show that more exercise compared to creating a higher caloric deficit has less of a negative effect on leptin levels and hormonal signals. Hunger signals are stronger when there is a calorie deficit however when exercise causes the deficit those hunger signals are generally not there (provided the deficit created from exercise isn’t excessive).

When it comes to exercise one also has to consider how the deficit is created. Weightlifting is the number one option to create a deficit because it helps maintain lean body mass. Remember we want to maintain muscle mass. Aerobic exercise can create a deficit, but may need to be done at least 3-4 times a week in order to fully account for that deficit. For some it may be way too intense to train for 100% of the deficit in one session.

There are studies which state the best way to create a deficit is though a combination of both exercise (weightlifting specifically) and diet. One study in particular done by Miller T et. al. found that resistance training and diet showed more fat loss and gain in lean body mass and this was done without aerobic exercise.

There are also things we need to address in determining how much of a deficit to create from cutting calories. In general a smaller person needs to create a smaller deficit.

We want to be extremely careful to not take a person below the critical energy balance and sending that person back into the “metabolic shit hole” so it’s not smart to just choose a number (i.e. 500 calories) and cut. There needs to be some forethought put into the amount of the deficit we want to create.

The problem with simply choosing one number to take out of the diet is that different women eat different amounts. For example say you had a woman eating 3,000 calories a day and a woman who is eating 2200 calories a day. Both decide to take out 500 calories. For the first woman who is eating 3000 calories this 500 calorie deficit would cause her little to no stress due to the fact that 2,500 is still enough food for her to function and feel fine. On the other hand the second woman would be down to 1,700 calories which may be below her critical threshold. (for reference Critical Threshold is 13.6cal/lbs Lean Body Mass). If she goes below her critical threshold she could then face some adverse effects on her health or enter a “metabolic shit hole”.

So rather than just cut a number each woman needs to assess the percentage of calories being taking out of her diet and also take into account her body fat ensuring they don’t go below that critical threshold. Remember that A slow fat loss journey (especially for the smaller female) is ideal.

A healthy deficit would be around 20% of a person’s maintenance calories. This means someone with higher caloric intake would have a greater number of calories to remove from the diet, while a smaller female with lower caloric intake would have a smaller reduction. Note that dropping lower than 30% of maintenance calories may cause dieter to fall so low on their calories, they are at risk of dropping below the critical energy availability threshold causing hormonal issues.

In general a good weight loss goal is 1-2 lbs per week. A lighter woman should shoot for 0.5-1 pounds weekly while heavier women should shoot for 1.5-2 pounds weekly. Heavier women with more body fat can lose weight faster than smaller women with lower body fat.

Another potential way to look at weight loss is by percentage of body weight. If your goal is to lose 10% of your body weight, you can break that down to 1% a week over 10 weeks. A good rate for lean females is 0.5% weekly, average women with more weight to lose would be around 1% and heavy or obese women are 1-1.5% of bodyweight.

The key to all this is a slow and steady weight loss. This may seem like a slower road than you’re willing to take but having realistic expectations is crucial. Many women expect a higher rate of weight loss (or fat loss, which is better than just losing muscle) and get disappointed with the realistic rate of which body fat can be lost safely and permanently. Do things right and don’t cut corners so you set yourself up for long term success.

Sources

Levine, James. A. (2004). Non-Exercise Activity Thermogenesis (Neat). Nutrition Reviews, Volume 62 (Issue suppl_2), Pages S82–S97.

McDonald, Lyle. (2017) The Women’s Book. Austin, Tx: Lyle McDonald Publishing.

Miller T el. al. Resistance Training Combined With Diet Decreases Body Fat While Preserving Lean Mass Independent of Resting Metabolic Rate: A Randomized Trial. Int J Sport Nitr Exerc Metab. (2017) 5:1-24.