Tips for Exercising When in a Calorie Deficit

While Calorie deficits are made easier with the aid of exercise, they can also take a toll on your body. This is especially true for those who dive into exercise for the first time (or after a long break) because they see it as a necessary step for fat loss. Others, like physique competitors or athletes, may be used to pushing themselves but don’t always realize how a deficit impacts recovery. So while this article can help you “accelerate fat loss” it can also help you protect yourself and set you up for long-term success.

We’ll cover strategies to sustain fat loss while also protecting muscle and overall health, so you can balance performance, recovery, and your fat loss goals effectively.

Let’s dig in!

The value of exercise

Exercise is often tied to fat loss, but that’s not really the main reason to do it. One of my first pieces of advice is not to look at exercise as a driver of fat loss but instead as something you’re looking to integrate regardless of if you’re trying to lose fat. For those of you who are athletes, this is a bit of preaching to the choir — but I’ll get to you in a moment. 

If you are someone who has always associated exercise with dieting or fat loss and you are using this deficit as a chance to build a training habit, that is great. Ideally the goal is to make exercising stick long-term. At the same time, it is important to consider how training in a deficit differs from training in a fully fed state.

So, why exercise? 

I’m sure at this point you’ve heard all the benefits of exercise in general (here, here, and here). Let’s focus on the biggest selling point — exercise plays a huge role in determining the kind of weight you lose. Without resistance training, a larger chunk of the weight you lose can come from muscle. But if you keep training, especially with some form of resistance training, you are likely to hold onto more lean mass and prioritize fat loss instead.

And ultimately while I do think exercise can positively impact fat loss, our biggest importance should be protecting muscle mass. With that in mind, one consideration is how much we ramp up our daily energy deficits.

A meta-analysis from Murphy and Koehler found that lean mass losses increased as daily energy deficits grew. When deficits stayed under 500 Calories per day (corresponding to rates of weight loss of 1 pound [0.5 kg] per week or less), subjects even saw a degree of body recomposition (losing fat while gaining a bit of muscle). However, once deficits exceeded 500 Calories per day, their lean mass losses increased.

So, a simple takeaway here is to focus on training smarter, not harder and that usually starts with finding the right rate of loss.

Finding the right weight loss rate for your training

Your rate of weight loss will depend on your training, your goals and, to some degree, how much discomfort you’re willing to tolerate. Generally speaking, I err on being more cautious and taking a slower pace when possible. That said, a cut that is too slow can feel frustrating if motivation starts to wane. The goal here is to try to strike the best balance when selecting your rate.

While faster cuts (closer to 1% per week) can work, they can come with more risk of muscle loss or general fatigue and hunger increases. Slower rates (closer to 0.25–0.5%) are more sustainable and might even allow for slight muscle gain.

Ultimately, we recommend starting with a rate between 0.25–1% of body weight per week and adjusting based on how you feel. A more moderate approach is usually best if you don’t have a hard deadline for your deficit. You can use the table below and/or this cutting calculator to find a target that balances effectiveness with sustainability.

A brief statement on RED-S for athletes and those seeking more competition-level body fats

Those who participate in sports, or train regularly, can be at a higher risk of experiencing low energy availability. Low energy availability (LEA) is a state when Calorie intake is not adequate to meet training or recovery demands. This can also lead to Relative Energy Deficiency in Sport (RED-S), which shows itself via declining performance, poor recovery, hormonal disruptions, increased risk of stress fractures, and more. It’s not uncommon for athletes to not even realize they are in a state of insufficient nutrition, and it affects both female and male athletes. 

Some individuals might not even consider the intensity or type of consistent training they do to fall into an athletic category. A study from McKinney et al proposed a categorization of athletes, and you could utilize this as a rough guide to help categorize the intensity or level of training you’re participating in. 

From McKinney et al (2019)

For those training at higher intensities and maintaining lower body fat levels, whether or not they’re preparing for a competition, it’s important to consider both the intensity and volume of training when deciding the timing of your cut. For example, say a wrestler wants to drop to a lower weight class mid-season. Losing a few pounds of fat over a couple of weeks might not seem like a big deal, especially if they’ve done it before without issue. But sustaining high training volumes in what they might consider a moderate deficit could negatively impact performance in matches or training sessions. In most cases, they would likely be better off keeping intake higher during the season and saving the cut for the off-season.

While I’m not going to specify hard guidelines (e.g., elite athletes should not attempt fat loss greater than 5%), I would argue that the more intensive your athletic schedule, the more we recommend sticking to conservative levels of fat loss to avoid unnecessary negative repercussions from energy restriction. 

Tips for exercising when in a deficit

Prioritize resistance training 

Since we are restricting calories during fat loss to decrease body mass, ideally we’d like most of that loss to come from fat mass (versus muscle mass). Resistance training plays a large role in helping allocate the partitioning of that mass and protecting (and even gaining) muscle during a deficit. It can also give us an edge on fat loss. A systematic review and meta-analysis by Lopez et al examined the effects of resistance training on body composition in individuals who are overweight or obese. Compared with no exercise, resistance training reduced body fat by an average of 1.6%. When combined with caloric restriction, body fat percentage was reduced by 3.8%.

For training frequency, it’s best to work most major muscle groups at least twice a week, focusing on compound exercises that engage multiple muscles simultaneously. For example, with the bench press you get work across your chest, triceps, and shoulders in just one movement, whereas isolation exercises mostly hit one muscle group. To be clear, if all you can manage is a few isolation exercises here and there, that’s still better than nothing. But if you’re setting up a program, a twice-weekly resistance training plan centered on compound exercises is a solid starting point. Realistically, each session would probably last around 45 to 60 minutes. As you add more training days, you’ll need to spread out your total volume, which could mean shorter but more frequent sessions. There isn’t really a wrong way; it just needs to be sustainable.

Lastly, if you’re diving into resistance training for the first time (or after a long time off) during a fat-loss phase, ease into volume and intensity each week. Injury can halt momentum just as much as poor movement on the scale. 

Aerobic training

Obviously I believe in the importance of resistance training in fat loss, but I would also like to emphasize the importance of aerobic work when in a deficit.

For aerobic activity during a deficit, a good target for weekly aerobic sessions would be 2–4 total sessions, lasting 20–40 minutes at a time. The activity could be jogging, incline walking, elliptical, cycling, or really whatever you feel suits your situation and access best. The goal is not to get too high in heart rate, staying in the 120–135 bpm range or using the talk test (you should be working hard enough that your breathing is noticeable but still light enough to hold a conversation).

The benefits of implementing this aerobic activity also goes beyond just activity increases. For example, it can help with appetite regulation. While it might seem that moving less would lead to eating less, research suggests that isn’t always the case. Below a certain activity threshold, appetite regulation can become less effective, and people who are sedentary can end up eating more than they burn, often without realizing it.

Energy compensation and reductions in non-exercise activity thermogenesis often occur during a deficit, leading to a gradual decline in overall activity and potential weight loss stalls. Research suggests that as activity levels increase, the body may compensate by reducing energy spent on other processes, making total energy expenditure less predictable. Therefore if we incorporate consistent aerobic activity during a deficit, while it won’t fully prevent metabolic adaptations (nor should it), it can help maintain a more stable energy balance and keep weight loss on track.

Finally, a study by Marks et al found that combining diet with resistance training resulted in slightly greater reductions in fat mass and body fat percentage than dieting alone. 

Nutrition considerations 

When exercising during a deficit, your nutrition needs to be more than just cutting calories. Ideally, you need to create the best nutrition setup that maximizes your ability to recover and sustain a deficit. Obviously, it needs to be realistic, and you don’t have to go overboard with a maximalist attitude. That said, the more aggressive the deficit, the more you need to ensure you’re meeting your biggest nutritional needs.

Protein intake: Again, in a deficit we are more at risk for loss of muscle mass. While resistance training helps mitigate that, getting enough protein adds another layer of protection. The best approach is to combine the two while keeping your training intensity and calorie deficit within a reasonable range. Also, as a general rule, it makes sense to structure your carb and fat intake around your protein needs.

Carbohydrate and fat intake: Since we prioritize protein intake, it means the rest of your nutrition will need to be divided appropriately between carbohydrates and fat. At a point, there is no perfect setup, and something will always have to be less than optimal (yet another argument to keep your deficit within a reasonable range). At the very least you need to ensure you’re getting your essential fatty acids. From there, I’d keep fiber intake up to recommended levels. After that, you’re basically eating for sustainability and training support. For those taking part in longer and more intense cardio sessions during a deficit period, I’d keep that in mind and consider cycling between deficit and maintenance days if needed.

Recovery

A lot of people focus on training hard but do not put the same effort into recovery. This becomes a bigger problem during a cut when recovery demands increase while energy availability decreases. This is not something only beginners struggle with; experienced lifters fall into the same trap, pushing through fatigue without a solid plan. So, what does good recovery actually look like?

Nutrition: Get adequate intake of all macro and micronutrients. It’s not just about protein. From vitamins to essential fatty acids, it all plays its part. This would also include proper fiber intake and hydration since there can be a decrease in overall whole food intake and dehydration during deficit events.

Sleep: It might be a hot take, but sometimes getting an extra hour of sleep is better than forcing a training session. If you have a night of less-than-ideal sleep, it might be better to sleep in and fit in a less-than-perfect workout (or even no workout). Then, on more rested days, you can push harder in the gym. This becomes even more important during a deficit when recovery is already compromised.

Training periodization: If you’re in a deficit, you’re probably not hitting your performance best, but that doesn’t mean your training should be aimless. A structured approach will do a much better job of preserving strength and muscle than just winging it. For some, an undulating periodization (varying intensity and volume within a week) could help manage fatigue while maintaining performance. That said if you’re newer to lifting, a simple linear progressive overload still works fine. The overall key is flexibility and being open to adjusting volume and intensity based on your actual recovery versus sticking to a plan just because it’s the plan.

Active recovery: It might seem counterintuitive, but keeping some low-intensity movement like walking, light cycling, or stretching can actually help with recovery. These activities increase blood flow, reduce stiffness, and may even promote better muscle recovery by breaking up long periods of sitting. The key is ensuring it stays in the sweet spot where it aids recovery rather than adding fatigue or interfering with performance.

Consistency and predictably allows insight 

Lastly, predictability is underrated for troubleshooting and helps you catch potential issues early. If your workouts have been going smoothly, but you suddenly start feeling rundown or your performance drops, that’s a clue. For example, if you’re consistently training and notice that in your last few workouts you’ve been weaker, and are taking longer to recover between sessions, this is valuable feedback. You can use that feedback to make the proper adjustments, be it taking a break from the deficit or considering a decrease in your weight loss rate to avoid burn out.

Take home 

For everything I covered here, you can boil it down to a few key points:

• Exercise is important across the board, but it’s especially useful during a deficit.
• The more aggressive the Calorie deficit, the greater the risk of muscle and performance loss.
• The goal is to find a sustainable deficit that creates momentum without running you into the ground.
• A structured, progressive resistance training plan helps track progress and can catch signs of performance loss or recovery issues that might indicate a need for a break or a less aggressive deficit.
• Aerobic work is valuable for fat loss, but high-intensity cardio should probably be used more strategically rather than as a default.
• When nutrition is lacking, maximizing recovery becomes even more important. Prioritizing sleep and nutrient-dense foods can help with the physical stress of a deficit. 
• Consistency in training makes it easier to track progress and spot changes in performance.