Will A Party Ruin Your Fat Loss Progress?

You’re in the middle of a training plan. Motivation is high, your nutrition is dialed in and you can see progress in the mirror. Life is great. Then something comes up that might throw a spanner in the works! You’ve been invited to a birthday, work party or barbecue. And you know this is going to be a big one. You don’t want to be that person who passes on the birthday cake because you’re “on a diet”. Or the one who takes a small plate of salad at the barbecue. That co-worker of yours has been at the company for years, you have to celebrate with them before they leave the place! But what about your progress!? I’m here today to tell you why you should have no fear. You can enjoy the food on offer, have a great time and not fall off the wagon.

What The Science Says

Studies over the years have shown that the consumption of a massive amount of calories from a single meal or several meals over a very short period actually lead to very little fat gain. In one study the researchers fed the subjects a meal of bread, jam and fruit juice. 480 grams of carbs, 8 grams of fat and a tiny amount of protein coming to around 1900 calories in the single meal. They then tracked the subjects’ metabolic responses over 10 hours.

The majority of the carbs were converted to glycogen (what our muscles and liver store and use as fuel). The rest of the carbs were burned up and just 2 grams were converted to fat. However, in the 10 hour period after the meal they burned 17 grams of fat so there was no actual fat gain from that one meal. So no need to worry about fat gain from one meal.

But what about several meals like this over a week?

A study done at the University of Colorado involved 16 people who were fed 50% over their daily maintenance calories for two weeks. Each subject gained about 0.2 pounds of fat a day. Another study at the Pennington Biomedical Research Center involved 29 men who were fed 40% more than their daily maintenance calories for 8 weeks. They each gained about 0.2 pounds of fat a day. This would show that there’s a limit to fat gain per day.

But another study, this one conducted at Loughborough University, took 15 normal weight individuals and fed them 78% more calories than needed for maintenance over the course of a single day and the average “weight gain” was 1.76 pounds. That’s an awful lot more than just 0.2 pounds of fat. This just shows that fat gain and weight gain are two different things. Just like fat loss and weight loss are completely different also.

Know The Difference

You see you can gain weight if you go bananas at an event like the ones I mentioned. But hardly any of that weight is actually fat, especially if it’s a one off or limited to a few hefty meals on a one week holiday for example. The weight you gain from a big meal or a week holiday of excess (as the case often is) will be lost in a couple days. Let me explain.

The first thing to note is carb intake. As the first study above showed, much of your carbs will be stored in the muscles and liver as glycogen. For each gram of stored carbohydrate you normally get 3 grams of water with it. This is why you see rapid weight loss on very low or zero carb diets. When you stop eating carbs, your body uses up more glycogen and for every gram of glycogen used up you also lose the 3 grams of water. Guess what happens when you eat more carbs again? You put back on the water weight!

Secondly most large meals would have a higher amount of sodium in them. This sodium makes your body retain water as well. Added to the extra water held in the glycogen and you could have a few pounds of fluid hanging around. That’s why it can be quite frustrating if you weigh yourself every day and see fluctuations all over the place. A lot of the time its not fat that is being gained or lost every day but the amount of fluid that’s in your system and muscles.

Take Home Message

Don’t be anxious about events like these throwing you off your game. If you use the habits I’ve mentioned previously like eating slowly and eating until 80% full you’re less likely to overeat but can still enjoy the foods at these events. Another tip is to do a workout on the day of these things. If your muscles use up glycogen while training then you “make a hole” for the carbs you’ll have at the event to go into. The food should replenish your glycogen stores and offset some of the possible weight gain. Know that that weight gain isn’t all fat, just up to 0.2 pounds of it. Most likely you’ll be back to your previous weight within a couple days.


KJ Acheson, et al. Glycogen synthesis versus lipogenesis after a 500 gram carbohydrate meal in man,” Metabolism, 1982, Dec 31 (12):1234-40.

TJ Horton, et al. “Fat and carbohydrate overfeeding in humans: different effects on energy storage,” Clin Nutr. 1995 Jul;62(1):19-29

Darcy Johannsen, et al. “Effect of 8 Weeks of Overfeeding on Ectopic Fat Deposition and Insulin Sensitivity: Testing the ‘Adipose Tissue Expandability’ Hypothesis,” Diabetes Care, 2014, oct; 37(10):2789-2797.

Jim Schwarz, et al. “Short-term alterations in carbohydrate energy intake in humans. Striking effects on hepatic glucose production, de novo lipogenesis, lipolysis, and whole-body fuel selection,” J Clin Invest 1995, Dec;96(6):2735-43.

Francis Mason, et al. “Effectiveness of a brief behavioural intervention to prevent weight gain over the Christmas holiday period: randomised controlled tria,” BMJ, 10 December, 2018.

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