HIIT or Strength Training for Fat Loss? What Our Coaches Programme, With the Calorie Maths

"I want to lose weight" is the most common first sentence we hear. But when we read our own class recordings, something else came up far more often once people were training.

Method: from 101 readable recordings of YourTrainer coaching classes, 17 August to 7 September 2026 (26 members, 4 coaches, mostly one-to-one). Percentages are shares of those classes. Members are anonymised; coach lines are quoted from class by first name.

What people say they want, once they start

Weight loss gets people through the door. Strength is what they talk about once they feel it. That is the first clue to the HIIT versus weights question.

The calorie maths of HIIT

Our HIIT500 live class burns roughly 300 to 500 kcal in 45 minutes, depending on bodyweight and effort. Here is what that adds up to across a week.

The last column uses about 7,700 kcal per kg of body fat, the rough figure most dietitians use. Useful, but small next to food. One coach put it to a member plainly: burn 300 in class, eat 2,000 against a 1,250 target, and there is no loss. In our classes calories came up in 25% of sessions, and food targets for women's fat loss were usually 1,200 to 1,600 kcal.

"Calorie eat and calorie out. Ultimately it will be calculated." (Coach Tanmana, in class)

Why strength comes first anyway

• It decides what the weight loss is made of. In a calorie deficit without strength work, part of what you lose is muscle. Lifting tells the body to keep it.
• It shows up fast. Coaches raised the load in 75% of our classes when form held. One member went from an 8 lb goblet squat to 10 to 20 lb in 16 days. That progress keeps people coming back.
• It fixes the "toned" goal. Our coaches correct this in class often: toned is not a separate thing. It means more muscle and less fat.
• The scale lies in the middle. Muscle, water and bone density can hold weight steady while you lose fat. Coaches ask members to use a tape and photos, not only the scale.

"Don't fixate on that weight number, because you're building muscle and losing fat at the same time." (Coach Vivek, in class)

Where HIIT earns its place

HIIT is the fitness engine. It makes stairs, sport and long days easier, adds a real calorie burn, and takes less time than steady cardio. It fails when it replaces strength or when form falls apart late in a circuit, which is when knees cave and backs round. That is why we coach it live with a small group, and why every move has a low-impact version.

The weekly mix we use

This is the mix most members choose in YourTrainer Live: Strength & Conditioning on Monday, Tuesday, Thursday and Friday, and HIIT500 on Wednesday and Saturday, coached live in classes of 6 or fewer.

Related reading

• Resistance training for weight loss, from our coached sessions
• Building strength with light dumbbells: 8 real progressions
• The 4 numbers our coaches track