General Fitness & Nutrition: Can I eat all the calories I burn in one day?

I bet that your nutrition source has to make some assumptions about your daily activity, probably based on your BMI and an average activity level.  My take is that you'll need to increase your calories for all those extra calories you're burning in each ride.  If you burn 1500-1700 calories on a ride, and eat less then 2000, I bet you'll feel very weak, bonk, and not have enough strength for daily activities if you keep it up.  You'll probably put your body in starvation mode and your metabolism will drop, making it difficult to lose weight in a sustainable way. 

Those are some long rides to burn that many calories, I bet if you keep your portions reasonable, you'll still lose weight without having to count calories.

Maybe some nutrition/diet experts will weigh in.

Marten

I belong to a weight-loss website. It gives you a number of calories each day to allow you to lose a safe amount of weight in a week (usually it`s your maintenance calories less 500 - so you would lose a pound a week).

That number assumes you aren't exercising. You have to enter both the food you eat and your exercise calories. And here's the rule: you have to eat back your exercise calories so that you get to your (net) "lose" total. For example, if my lose calories for the day are 1200, but I burn 600 in exercise, then I have to eat 1800 calories that day.

The risk if you don't do that is exactly what the earlier poster said - you will feel weak and your body may go into starvation mode. This leads to frustration and makes it less likely that your weight loss will succeed.

Interesting article about the 'myth' of starvation mode versus reduced metabolic rate over here ... http://www.weightwatchers.co.uk/util/art/index_art.aspx?tabnum=1&art_id=29241

 Either way, I think the principle is right and it's mostly semantics.

If you are burning that many calories you will need to add more calories in. I recommend recording what you eat for three days. Don't try to limit your calories - try to make healthy choices, eat when you are hungry, and stop eating when you are full. You can go to MyPyramid.gov and use the MyPyramid tracker to check your calorie intake. Do this for 3 days to get an average. If it is close to 2000 I could not cut anything out. If it is closer to 3000, see if you can cut calories back a little without leaving yourself starved. Slow, gradual weight loss has been show to be the most sustainable over and over again (quick fixes don't work), so try to find little ways to cut back calories. If you would like to best results, I recommend you see a Registered Dietitian who specializes in athletes. If you are in the US you can locate a Registered Dietitian specializing in sports here: http://www.scandpg.org/mapsearch.php

The link on the "starvation myth" is just saying that your metabolism does slow down when you cut calories, but you can still lose weight, just at a slower rate. It is not really debunking any myth - it specially says your metabolism will slow down so your rate of weight loss will be slowed. As we know, the metabolism will picks back up once weight loss is stopped.

Regardless, when your fat cells shrink (which is what they do with weight loss - they can never go away) they secrete less of a hormone that tells you that you are full (letpin). When you have less of this hormone too quickly you will feel hungrier and "dieting" will be difficult. With my background in nutritional biochemistry and human biology I am still a firm believer than your body is smarter than you and if you restrict calories too much it will compensate by eventually decreasing your metabolic rate in an effort to conserve energy.

Don't know about biking but...I up my calories and carbs two days before a long run. Eat on the run and 4:1 Carbs:Protein as soon as I cool-down and stretch. I don't eat all the calories on one day but spread them out and save some for the day after the long run.

 Ben