Carbs at Night: Study Finds They Don’t Affect Fat Loss When Calories Are Equal

Key Summary of Carbs at Night Article:

• The study found that eating carbs at night versus earlier in the day doesn’t have a big effect on fat loss or muscle gain as long as the total number of calories and nutrients eaten each day are the same.
•  No matter when you eat carbs, regular exercise, and a well-balanced, flexible diet will help your body shape and health.
• You might not need to avoid carbs at night. For long-term fitness goals, it’s much more important to focus on your daily nutritional needs and stick to a workout plan.

Carbs at Night Result in Fat Gain…Right?

It’s been said for years that people who don’t want to gain weight shouldn’t eat carbs at night. This idea comes from the belief that eating carbs late in the day makes you gain weight and store fat. Research indicates that nighttime eating can be associated with increased fat intake and altered metabolic responses, particularly in individuals with disrupted circadian rhythms, such as shift workers.¹  However, many have propagated the idea that consuming carbohydrates at night inherently causes weight gain and fat storage.. This idea is partially based on the carbohydrate-insulin hypothesis of obesity, which postulates that eating carbohydrates raises insulin levels, encouraging weight growth and fat storage.² Social media and false beliefs that carbohydrates are a major contributor to obesity have helped spread this view among the general population.³

This argument has become more complicated due to the new study of chrono-nutrition, which investigates how meal timing impacts metabolism. According to research, the body’s ability to metabolize glucose and retain fat is influenced by circadian rhythms, which are biological processes that occur on a 24-hour cycle.⁴ For example, studies have linked evening carbohydrate intake to poor lipid profiles and decreased glucose tolerance, especially in sedentary people, and late-night energy consumption to obesity.⁵ Clinical study outcomes, however, are still unclear, mainly when isocaloric circumstances are present, and total caloric intake is constant throughout the day.^5,6

New Study Challenges the Carbs at Night Theory

A recent study titled “Evaluating the Evening Carbohydrate Dilemma: The Effect of Within-the-Day Carbohydrate Periodization on Body Composition and Physical Fitness” by Angelos Vlahoyiannis and colleagues, published in the European Journal of Nutrition (2025), challenges this long-standing myth.² The study involved physically active men who followed different dietary strategies to examine how carb timing and type—such as low-glycemic versus high-glycemic carbs—affect fat loss, muscle gain, and physical performance. It was a surprise to the experts that eating carbs at night does not affect fitness or fat loss as long as the total number of calories and nutrients in the day is balanced. Based on these results, the “no carbs at night” rule needs to be rethought and replaced with more useful, scientifically proven eating plans.

Study Overview: Testing the “Carb at Night” Fat Gain Theory

The study involved 42 trained male participants divided into three groups:

Sleep Low-No Carbohydrate Group: This group consumed all their carbs before their evening workout.

Sleep High-Low Glycemic Index Group: 40% carbs after their evening workout, with low glycemic index foods. Low Glycemic Index Foods included Whole grains: Whole-wheat bread, parboiled or brown rice, whole-wheat pasta, and oats. Fruits and nuts: Green apples and walnuts.

Sleep High-High Glycemic Index Group: Similar to the second group, but participants consumed 40% high-glycemic index carbohydrates (such as white bread) in the evening. Refined grains: White bread, jasmine or basmati rice, boiled potatoes, and white spaghetti.

Fruits: Ripe bananas.

The people who took part followed a calorie-balanced meal that was made just for them for four weeks. 20% of the food was protein, 60% was carbs, and 20% was fat. These amounts were carefully kept the same for all groups to make sure that the results only showed the time and type of carbohydrates that were eaten.

Plan for working out

All of the subjects followed a structured five-day exercise plan that included:

Strength training: squats, bench pushes, and lat pull-downs were done three times for the whole body. At 80% of their one-repetition limit, the participants did four sets of eight reps each.

High-Intensity Interval Training: Twice a week, subjects performed ten one-minute sprints at 90% of their maximum aerobic ability, then rested for one minute.

Results: Carbs at Night Don’t Cause Fat Gain

Changes in Muscle and Fat:

• On average, participants lost 1.5% of fat.
• The rise in fat-free mass was about 2 pounds (0.9 kg).
• When total calories were balanced, there were no discernible variations in muscle gain or fat loss between groups, suggesting that the time and type of carbohydrates had no effect on body composition.

Physical Fitness Changes:

Every participant demonstrated notable progress in:

Aerobic Capacity: endurance was improved by an average 9.6% increase in VO2max.

Strength: Important activities like squats and bench presses showed notable increases.

Dispelling the Myth of Carb Timing

The findings show that the timing of carbohydrate (i.e., carbs at night) ingestion has no impact on body composition (i.e., fat gain or muscle gain) and physical fitness when total calorie and nutrient intake are regulated. The widely accepted notion that consuming carbohydrates at night causes weight gain or fat accumulation is refuted by this research. These results are consistent with previous research, which emphasizes that total calorie and macronutrient intake are more important than meal timing.

The Value of Exercise

The study emphasizes how important exercise is for enhancing fitness results. All groups had fat loss and muscle increase as a result of regular strength training and high-intensity interval sessions, demonstrating that exercise is more important than meal timing.

Flexible Diets Instead of Strict Plans

The results highlight the need for adaptable, sustainable dietary habits. Short-term adherence and detrimental psychological impacts, such as increased food cravings and weariness, are common outcomes of restrictive diets, such as avoiding carbs at night.^7,8 Individuals may customize their eating habits to suit their tastes with flexible regimens, which fosters long-term success and general well-being.

Real-World Uses

• Put Total Calories First: Don’t worry about when you consume carbs; instead, concentrate on getting enough energy each day.
• Exercise Frequently: To get the most out of your regimen, including high-intensity exercises and strength training.
• Select Nutrient-Dense Carbohydrates: For improved energy and recuperation, choose whole grains, fruits, and vegetables.
• Use Adaptable Diets: Steer clear of harsh limitations and create a sustainable strategy that fits your objectives and way of life.

References

1               Shan, Z. et al. Rotating Night Shift Work and Adherence to Unhealthy Lifestyle in Predicting Risk of Type 2 Diabetes: Results From Two Large US Cohorts of Female Nurses. BMJ, k4641 (2018). https://doi.org/10.1136/bmj.k4641

2               Vlahoyiannis, A. et al. Evaluating the evening carbohydrate dilemma: the effect of within-the-day carbohydrate periodization on body composition and physical fitness. European Journal of Nutrition 64 (2024). https://doi.org/10.1007/s00394-024-03540-6

3               Jauho, M., Pääkkönen, J., Isotalo, V., Pöyry, E. & Laaksonen, S.-M. How do trendy diets emerge? An exploratory social media study on the low-carbohydrate diet in Finland. Food, Culture & Society 26, 344-369 (2023). https://doi.org/10.1080/15528014.2021.1971436

4               Franzago, M., Alessandrelli, E., Notarangelo, S., Stuppia, L. & Vitacolonna, E. Chrono-Nutrition: Circadian Rhythm and Personalized Nutrition. International Journal of Molecular Sciences 24 (2023).

5               Xiao, Q., Garaulet, M. & Scheer, F. A. J. L. Meal timing and obesity: interactions with macronutrient intake and chronotype. International Journal of Obesity 43, 1701-1711 (2019). https://doi.org/10.1038/s41366-018-0284-x

6               Curioni, C. C. & Lourenço, P. M. Long-term weight loss after diet and exercise: a systematic review. International Journal of Obesity 29, 1168-1174 (2005). https://doi.org/10.1038/sj.ijo.0803015

7               Colombarolli, M. S., de Oliveira, J. & Cordás, T. A. Craving for carbs: food craving and disordered eating in low-carb dieters and its association with intermittent fasting. Eating and Weight Disorders – Studies on Anorexia, Bulimia and Obesity 27, 3109-3117 (2022). https://doi.org/10.1007/s40519-022-01437-z

8               Harvey, K. L., Holcomb, L. E. & Kolwicz, S. C. Ketogenic Diets and Exercise Performance. Nutrients 11 (2019).